Merge pull request #1857 from rouault/rfc4_doc_improvements

[RFC4_dev] Doc improvements

.cirrus.yml

@@ -16,7 +16,7 @@ task:
     folder: $HOME/.ccache
 
   pkginstall_script:
-    - pkg install -y autoconf automake libtool pkgconf sqlite3 wget unzip ccache gmake
+    - pkg install -y autoconf automake libtool pkgconf sqlite3 tiff wget unzip ccache gmake
   download_grid_script:
     - wget https://download.osgeo.org/proj/proj-datumgrid-1.8.zip
     - (cd data && unzip -o ../proj-datumgrid-1.8.zip)

CMakeLists.txt

@@ -83,6 +83,7 @@ elseif("${CMAKE_C_COMPILER_ID}" STREQUAL "Intel")
     set(PROJ_CXX_WARN_FLAGS -Wall)
   endif()
 endif()
+
 set(PROJ_C_WARN_FLAGS "${PROJ_C_WARN_FLAGS}"
   CACHE STRING "C flags used to compile PROJ targets")
 set(PROJ_CXX_WARN_FLAGS "${PROJ_CXX_WARN_FLAGS}"
@@ -133,6 +134,39 @@ IF("${SQLITE3_VERSION}" VERSION_LESS "3.11")
   message(SEND_ERROR "sqlite3 >= 3.11 required!")
 ENDIF()
 
+################################################################################
+# Check for libtiff
+################################################################################
+
+option(DISABLE_TIFF "Disable TIFF support" OFF)
+mark_as_advanced(DISABLE_TIFF)
+if(DISABLE_TIFF)
+  message(WARNING "TIFF support has been disabled and will result in the inability to read some grids")
+else()
+  find_package(TIFF REQUIRED)
+  if(TIFF_FOUND)
+    boost_report_value(TIFF_FOUND)
+  else()
+    message(SEND_ERROR "libtiff dependency not found!")
+  endif()
+  add_definitions(-DTIFF_ENABLED)
+endif()
+
+################################################################################
+# Check for curl
+################################################################################
+
+option(ENABLE_CURL "Enable Curl support" ON)
+if(ENABLE_CURL)
+  find_package(CURL REQUIRED)
+  if(CURL_FOUND)
+    boost_report_value(CURL_FOUND)
+  else()
+    message(SEND_ERROR "curl dependency not found!")
+  endif()
+  add_definitions(-DCURL_ENABLED)
+endif()
+
 ################################################################################
 # threading configuration
 ################################################################################

Doxyfile

@@ -772,7 +772,7 @@ WARN_LOGFILE           =
 # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = src/iso19111 include/proj src/proj.h src/proj_experimental.h src/general_doc.dox
+INPUT                  = src/iso19111 include/proj src/proj.h src/proj_experimental.h src/general_doc.dox src/filemanager.cpp src/networkfilemanager.cpp
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses

appveyor.yml

@@ -27,9 +27,10 @@ build_script:
   - set PATH=%CD%;%PATH%
   - cd ..
   - vcpkg install sqlite3:"%platform%"-windows
+  - vcpkg install tiff:"%platform%"-windows
+  - vcpkg install curl:"%platform%"-windows
   - set SQLITE3_BIN=%APPVEYOR_BUILD_FOLDER%\sqlite3\bin
   - mkdir %SQLITE3_BIN%
-  - copy c:\projects\proj\vcpkg\installed\"%platform%"-windows\bin\sqlite3.dll %SQLITE3_BIN%
   - ps: |
         appveyor DownloadFile https://sqlite.org/2018/sqlite-tools-win32-x86-3250100.zip
         7z x sqlite-tools-win32-x86-3250100.zip
@@ -50,6 +51,8 @@ build_script:
   - set PROJ_DIR=%APPVEYOR_BUILD_FOLDER%\proj_dir
   - cmake -G "%VS_FULL%" .. -DCMAKE_BUILD_TYPE=Release -DBUILD_LIBPROJ_SHARED="%BUILD_LIBPROJ_SHARED%" -DCMAKE_C_FLAGS="/WX" -DCMAKE_CXX_FLAGS="/WX" -DCMAKE_TOOLCHAIN_FILE=C:/projects/proj/vcpkg/scripts/buildsystems/vcpkg.cmake -DCMAKE_INSTALL_PREFIX="%PROJ_DIR%"
   - cmake --build . --config Release --target install
+  - copy c:\projects\proj\vcpkg\installed\"%platform%"-windows\bin\*.dll %PROJ_DIR%\bin
+  - dir %PROJ_DIR%\bin
 
 test_script:
   - echo test_script

cmake/ProjTest.cmake

@@ -2,6 +2,11 @@
 # add test with sh script
 #
 
+function(proj_test_set_properties TESTNAME)
+    set_tests_properties( ${TESTNAME}
+        PROPERTIES ENVIRONMENT "PROJ_IGNORE_USER_WRITABLE_DIRECTORY=YES;PROJ_LIB=${PROJECT_BINARY_DIR}/data/for_tests")
+endfunction()
+
 function(proj_add_test_script_sh SH_NAME BIN_USE)
   if(UNIX)
     get_filename_component(testname ${SH_NAME} NAME_WE)
@@ -26,8 +31,8 @@ function(proj_add_test_script_sh SH_NAME BIN_USE)
         COMMAND ${PROJECT_SOURCE_DIR}/test/cli/${SH_NAME}
         ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${${BIN_USE}}
       )
-    set_tests_properties( ${testname}
-        PROPERTIES ENVIRONMENT "PROJ_LIB=${PROJECT_BINARY_DIR}/data/for_tests")
+
+      proj_test_set_properties(${testname})
     endif()
 
   endif()
@@ -43,8 +48,6 @@ function(proj_add_gie_test TESTNAME TESTCASE)
       COMMAND ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${GIE_BIN}
       ${TESTFILE}
     )
-    set_tests_properties( ${TESTNAME}
-        PROPERTIES ENVIRONMENT "PROJ_LIB=${PROJECT_BINARY_DIR}/data/for_tests")
-
+    proj_test_set_properties(${TESTNAME})
 
 endfunction()

configure.ac

@@ -20,6 +20,8 @@ AC_PROG_LN_S
 AC_PROG_MAKE_SET
 AM_PROG_LIBTOOL
 
+PKG_PROG_PKG_CONFIG
+
 dnl Enable as much warnings as possible
 AX_CFLAGS_WARN_ALL(C_WFLAGS)
 AX_CXXFLAGS_WARN_ALL(CXX_WFLAGS)
@@ -169,6 +171,15 @@ AC_SUBST(NO_ZERO_AS_NULL_POINTER_CONSTANT_FLAG,$NO_ZERO_AS_NULL_POINTER_CONSTANT
 CFLAGS="${CFLAGS} -fvisibility=hidden"
 CXXFLAGS="${CXXFLAGS} -fvisibility=hidden"
 
+case "${host_os}" in
+    cygwin* | mingw32* | pw32* | beos* | darwin*)
+        CFLAGS="${CFLAGS} -DNOMINMAX"
+        CXXFLAGS="${CXXFLAGS} -DNOMINMAX"
+        ;;
+    *)
+        ;;
+esac
+
 dnl Checks for libraries.
 save_CFLAGS="$CFLAGS"
 CFLAGS=`echo "$CFLAGS" | sed "s/-Werror/ /"`
@@ -240,6 +251,78 @@ if test x"$SQLITE3_CHECK" != x"yes" ; then
     AC_MSG_ERROR([Please install sqlite3 binary.])
 fi
 
+dnl ---------------------------------------------------------------------------
+dnl Check for libtiff
+dnl ---------------------------------------------------------------------------
+
+AC_ARG_ENABLE([tiff-is-strongly-discouraged],
+              AS_HELP_STRING([--disable-tiff-is-strongly-discouraged],
+                    [Disable TIFF support. Strongly discouraged !]),
+              [enable_tiff=no],
+              [enable_tiff=yes])
+
+if test "x$enable_tiff" = "xyes" -o "x$enable_tiff" = ""; then
+    if test "x$TIFF_CFLAGS$TIFF_LIBS" = "x" ; then
+        if $PKG_CONFIG libtiff; then
+            PKG_CHECK_MODULES([TIFF], [libtiff])
+        else
+            PKG_CHECK_MODULES([TIFF], [libtiff-4])
+        fi
+    fi
+    TIFF_ENABLED_FLAGS=-DTIFF_ENABLED
+fi
+AC_SUBST(TIFF_CFLAGS,$TIFF_CFLAGS)
+AC_SUBST(TIFF_LIBS,$TIFF_LIBS)
+AC_SUBST(TIFF_ENABLED_FLAGS,$TIFF_ENABLED_FLAGS)
+
+dnl ---------------------------------------------------------------------------
+dnl Check for curl
+dnl ---------------------------------------------------------------------------
+
+FOUND_CURL=no
+CURL_CFLAGS=
+CURL_LIB=
+
+AC_ARG_WITH(curl,
+    [  --with-curl[=ARG]       Enable curl support (ARG=path to curl-config.)],,,)
+
+dnl Clear some cache variables
+unset ac_cv_path_LIBCURL
+
+if test "`basename xx/$with_curl`" = "curl-config" ; then
+  LIBCURL_CONFIG="$with_curl"
+elif test "$with_curl" = "no" ; then
+  LIBCURL_CONFIG=no
+else
+  AC_PATH_PROG(LIBCURL_CONFIG, curl-config, not-found)
+fi
+
+if test "$LIBCURL_CONFIG" = "not-found" ; then
+  AC_MSG_ERROR([curl not found. If wanting to do a build without curl support (and thus without built-in networking capability), explictly disable it with --without-curl])
+elif test "$LIBCURL_CONFIG" != "no" ; then
+
+  CURL_VERNUM=`$LIBCURL_CONFIG --vernum`
+  CURL_VER=`$LIBCURL_CONFIG --version | awk '{print $2}'`
+
+  AC_MSG_RESULT([        found libcurl version $CURL_VER])
+
+  AC_CHECK_LIB(curl,curl_global_init,FOUND_CURL=yes,FOUND_CURL=no,`$LIBCURL_CONFIG --libs`)
+
+  if test "$FOUND_CURL" = "no" ; then
+    AC_MSG_ERROR([curl not found. If wanting to do a build without curl support (and thus without built-in networking capability), explictly disable it with --without-curl])
+  fi
+  CURL_ENABLED_FLAGS=-DCURL_ENABLED
+fi
+
+if test "$FOUND_CURL" = "yes" ; then
+  CURL_CFLAGS=`$LIBCURL_CONFIG --cflags`
+  CURL_LIBS=`$LIBCURL_CONFIG --libs`
+fi
+
+AC_SUBST(CURL_CFLAGS,$CURL_CFLAGS)
+AC_SUBST(CURL_LIBS,$CURL_LIBS)
+AC_SUBST(CURL_ENABLED_FLAGS,$CURL_ENABLED_FLAGS)
+
 dnl ---------------------------------------------------------------------------
 dnl Check for external Google Test
 dnl ---------------------------------------------------------------------------

data/CMakeLists.txt

@@ -2,6 +2,10 @@
 # files containing dictionary of useful projection
 #
 
+set(CONFIG_FILES
+  proj.ini
+)
+
 set(PROJ_DICTIONARY
   null
   world
@@ -54,7 +58,7 @@ add_custom_command(
 add_custom_target(generate_proj_db ALL DEPENDS ${PROJ_DB})
 
 if(NOT "${CMAKE_CURRENT_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_BINARY_DIR}")
-  foreach(FILE ${PROJ_DICTIONARY} ${GRIDSHIFT_FILES})
+  foreach(FILE ${CONFIG_FILES} ${PROJ_DICTIONARY} ${GRIDSHIFT_FILES})
     configure_file(${FILE} ${FILE} COPYONLY)
   endforeach()
 endif()
@@ -78,18 +82,25 @@ set(DATA_FOR_TESTS
     nzgd2kgrid0005.gsb
     ITRF2000
     BETA2007.gsb)
+file(GLOB DATA_TESTS tests/*)
 
 execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/for_tests)
-foreach(FILE ${DATA_FOR_TESTS})
+execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/for_tests/tests)
+foreach(FILE ${DATA_FOR_TESTS} ${CONFIG_FILES})
     if (EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${FILE})
         configure_file(${CMAKE_CURRENT_SOURCE_DIR}/${FILE} ${CMAKE_CURRENT_BINARY_DIR}/for_tests/${FILE} COPYONLY)
     endif()
 endforeach()
+foreach(FILE ${DATA_TESTS})
+    get_filename_component(FILENAME ${FILE} NAME)
+    configure_file(${FILE} ${CMAKE_CURRENT_BINARY_DIR}/for_tests/tests/${FILENAME} COPYONLY)
+endforeach()
 
 #
 #install
 #
 set(ALL_DATA_FILE
+  ${CONFIG_FILES}
   ${PROJ_DICTIONARY}
   ${GRIDSHIFT_FILES}
   ${PROJ_DB}

data/Makefile.am

@@ -1,6 +1,6 @@
 DATAPATH = $(top_srcdir)/data
 
-pkgdata_DATA = GL27 nad.lst nad27 nad83 world other.extra \
+pkgdata_DATA = proj.ini GL27 nad.lst nad27 nad83 world other.extra \
 		CH null \
 		ITRF2000 ITRF2008 ITRF2014 proj.db \
 		projjson.schema.json
@@ -38,12 +38,55 @@ SQL_ORDERED_LIST = sql/begin.sql \
 		sql/customizations.sql \
 		sql/commit.sql
 
-EXTRA_DIST = GL27 nad.lst nad27 nad83 \
+EXTRA_DIST = proj.ini GL27 nad.lst nad27 nad83 \
 		world other.extra \
 		CH \
 		ITRF2000 ITRF2008 ITRF2014 \
 		projjson.schema.json \
-		CMakeLists.txt tests/test_nodata.gtx null \
+		CMakeLists.txt \
+		tests/test_nodata.gtx \
+		tests/test_vgrid_bigendian_bigtiff.tif \
+		tests/test_vgrid_bigendian.tif \
+		tests/test_vgrid_bigtiff.tif \
+		tests/test_vgrid_bottomup_with_matrix.tif \
+		tests/test_vgrid_bottomup_with_scale.tif \
+		tests/test_vgrid_deflate_floatingpointpredictor.tif \
+		tests/test_vgrid_deflate.tif \
+		tests/test_vgrid_float64.tif \
+		tests/test_vgrid_in_second_channel.tif \
+		tests/test_vgrid_int16.tif \
+		tests/test_vgrid_int32.tif \
+		tests/test_vgrid_uint32.tif \
+		tests/test_vgrid_invalid_channel_type.tif \
+		tests/test_vgrid_nodata.tif \
+		tests/test_vgrid_pixelisarea.tif \
+		tests/test_vgrid_pixelispoint.tif \
+		tests/test_vgrid_uint16.tif \
+		tests/test_vgrid_uint16_with_scale_offset.tif \
+		tests/test_vgrid_unsupported_byte.tif \
+		tests/test_vgrid_with_overview.tif \
+		tests/test_vgrid_with_subgrid.tif \
+		tests/test_hgrid.tif \
+		tests/test_hgrid_separate.tif \
+		tests/test_hgrid_tiled.tif \
+		tests/test_hgrid_tiled_separate.tif \
+		tests/test_hgrid_strip.tif \
+		tests/test_hgrid_positive_west.tif \
+		tests/test_hgrid_lon_shift_first.tif \
+		tests/test_hgrid_radian.tif \
+		tests/test_hgrid_degree.tif \
+		tests/test_hgrid_with_overview.tif \
+		tests/test_hgrid_extra_ifd_with_other_info.tif \
+		tests/test_hgrid_with_subgrid.tif \
+		tests/test_hgrid_with_subgrid_no_grid_name.tif \
+		tests/subset_of_gr3df97a.tif \
+		tests/egm96_15_uncompressed_truncated.tif \
+		tests/test_vgrid_single_strip_truncated.tif \
+		tests/nkgrf03vel_realigned_extract.tif \
+		tests/nkgrf03vel_realigned_xy_extract.ct2 \
+		tests/nkgrf03vel_realigned_z_extract.gtx \
+		tests/test_hgrid_with_two_level_of_subgrids_no_grid_name.tif \
+		null \
 		generate_all_sql_in.cmake sql_filelist.cmake \
 		$(SQL_ORDERED_LIST)
 
@@ -127,6 +170,8 @@ check-local:
 			echo "WARNING: grid $$x missing: some tests will be skipped"; \
 		fi \
 	done; \
+	ln -sf ../$(DATAPATH)/tests for_tests; \
+	ln -sf ../$(DATAPATH)/proj.ini for_tests; \
 	ln -sf ../proj.db for_tests
 
 clean-local:

data/proj.ini

@@ -0,0 +1,16 @@
+[general]
+; Lines starting by ; are commented lines.
+;
+
+; Network capabilities disabled by default.
+; Can be overriden with the PROJ_NETWORK=ON environment variable.
+; network = on
+
+; Can be overriden with the PROJ_NETWORK_ENDPOINT environment variable.
+cdn_endpoint = https://cdn.proj.org
+
+cache_enabled = on
+
+cache_size_MB = 300
+
+cache_ttl_sec = 86400

docs/source/apps/cct.rst

@@ -91,6 +91,17 @@ cartesian coordinates) and
 *Coordinate Transformations*, which are coordinate operations where
 input and output datums differ (e.g. change of reference frame).
 
+Use of remote grids
+*******************
+
+.. versionadded:: 7.0.0
+
+If the :envvar:`PROJ_NETWORK` environment variable is set to ``ON``,
+:program:`cct` will attempt to use remote grids stored on CDN (Content
+Delivery Network) storage, when they are not available locally.
+
+More details are available in the :ref:`network` section.
+
 Examples
 ********
 

docs/source/apps/cs2cs.rst

@@ -171,6 +171,16 @@ normally be in DMS format (use ``-f %.12f`` for decimal degrees with 12 decimal
 places), while projected (cartesian) coordinates will be in linear
 (meter, feet) units.
 
+Use of remote grids
+-------------------
+
+.. versionadded:: 7.0.0
+
+If the :envvar:`PROJ_NETWORK` environment variable is set to ``ON``,
+:program:`cs2cs` will attempt to use remote grids stored on CDN (Content
+Delivery Network) storage, when they are not available locally.
+
+More details are available in the :ref:`network` section.
 
 Examples
 ********

docs/source/apps/projinfo.rst

@@ -20,7 +20,7 @@ Synopsis
     |    [[--area name_or_code] | [--bbox west_long,south_lat,east_long,north_lat]]
     |    [--spatial-test contains|intersects]
     |    [--crs-extent-use none|both|intersection|smallest]
-    |    [--grid-check none|discard_missing|sort] [--show-superseded]
+    |    [--grid-check none|discard_missing|sort|known_available] [--show-superseded]
     |    [--pivot-crs always|if_no_direct_transformation|never|{auth:code[,auth:code]*}]
     |    [--boundcrs-to-wgs84]
     |    [--main-db-path path] [--aux-db-path path]*
@@ -151,12 +151,13 @@ The following control parameters can appear in any order:
 
     .. note:: only used for coordinate operation computation
 
-.. option:: --grid-check none|discard_missing|sort
+.. option:: --grid-check none|discard_missing|sort|known_available
 
     Specify how the presence or absence of a horizontal or vertical shift grid
     required for a coordinate operation affects the results returned when
     researching coordinate operations between 2 CRS.
-    The default strategy is ``sort``: in that case, all candidate
+    The default strategy is ``sort`` (if :envvar:`PROJ_NETWORK` is not defined).
+    In that case, all candidate
     operations are returned, but the actual availability of the grids is used
     to determine the sorting order. That is, if a coordinate operation involves
     using a grid that is not available in the PROJ resource directories
@@ -166,6 +167,9 @@ The following control parameters can appear in any order:
     this returns the results as if all the grids where available.
     The ``discard_missing`` strategy discards results that involve grids not
     present in the PROJ resource directories.
+    The ``known_available`` strategy discards results that involve grids not
+    present in the PROJ resource directories and that are not known of the CDN.
+    This is the default strategy is :envvar:`PROJ_NETWORK` is set to ``ON``.
 
     .. note:: only used for coordinate operation computation
 

docs/source/community/rfc/rfc-4.rst

@@ -695,613 +695,11 @@ choice.
 
 .. _description_geotiff_format:
 
-Description of the PROJ GeoTIFF format
-++++++++++++++++++++++++++++++++++++++
-
-The general principles that guide the following requirements and recommendations
-are such that files will be properly recognized by PROJ, and also by GDAL which
-is an easy way to inspect such grid files:
-
-- `TIFF 6.0 <https://www.awaresystems.be/imaging/tiff/specification/TIFF6.pdf>`_
-  based (could possibly be BigTIFF without code changes, if we ever
-  need some day to handle grids larger than 4GB)
-
-- `GeoTIFF 1.1 <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html>`_ for the georeferencing.
-  GeoTIFF 1.1 is a recent standard, compared to the original GeoTIFF 1.0 version,
-  but its backward compatibility is excellent, so that should not cause much trouble
-  to readers that are not official GeoTIFF 1.1 compliant.
-
-- Files hosted on the CDN will use a Geographic 2D CRS for the GeoTIFF GeoKeys.
-  That CRS is intended to be the interpolation CRS as defined in
-  `OGC Abstract Specification Topic 2 <http://docs.opengeospatial.org/as/18-005r4/18-005r4.html>`_,
-  that is the CRS to which grid values are refered to.
-
-  Given that they will nominally be related to the EPSG dataset, the `GeodeticCRSGeoKey
-  <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html#_requirements_class_geodeticcrsgeokey>`_
-  will be used to store the EPSG code of the CRS. If the CRS cannot be reliably
-  encoded through that key or other geokeys, the ``interpolation_crs_wkt`` metadata
-  item detailed afterwards should be used.
-
-  This CRS will be generally the source CRS (for geographic to
-  geographic horizontal shift grids, or geographic to vertical shift grids), but
-  for vertical to vertical CRS adjustment, this will be the geographic CRS to
-  which the grid is referenced. In some very rare cases of geographic to vertical
-  shift grids, the interpolation CRS might be a geographic CRS that is not the
-  same as the source CRS (into which ellipsoidal height are expressed). The only
-  instance we have in mind is for the EPSG:7001 "ETRS89 to NAP height (1)" transformation
-  using the naptrans2008 VDatum-grid which is referenced to Amersfoort EPSG:4289
-  instead of ETRS89...
-
-  On the reading side, PROJ will ignore that information:
-  the CRS is already stored in the source_crs or interpolation_crs column of the
-  grid_transformation table.
-
-  For geographic to vertical shift files (geoid models), the GeoTIFF 1.1
-  convention will be used to store the value of the `VerticalGeoKey
-  <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html#_requirements_class_verticalgeokey>`_
-  So a geoid model that apply to WGS 84 EPSG:4979 will have GeodeticCRSGeoKey = 4326
-  and VerticalGeoKey = 4979.
-
-- Files hosted on the CDN will use the GeoTIFF defined `ModelTiepointTag and ModelPixelScaleTag
-  <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html#_raster_to_model_coordinate_transformation_requirements>`_ TIFF tags
-  to store the coordinates of the upper-left pixel and the resolution of the pixels.
-  On the reading side, they will be required and ModelTransformationTag will be ignored.
-
-  .. note::
-
-    Regarding anti-meridian handling, a variety of possibilities exist.
-    We do not attempt to standardize this and filesh hosted on the CDN will use
-    a georeferencing close to the original data producer.
-    For example, NOAA vertical grids that apply to Conterminous USA might even have a top-left
-    longitude beyond 180 (for consistency with Alaska grids, whose origin is < 180)
-    Anti-meridian handling in PROJ has probably issues. This RFC does not attempt
-    to address them in particular, as they are believed to be orthogonal to the
-    topics it covers, and being mostly implementation issues.
-
-- Files hosted on the CDN will use the `GTRasterTypeGeoKey
-  <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html#_requirements_class_gtrastertypegeokey>`_
-  = PixelIsPoint convention.
-  This is the convention used by most existing grid formats currently. Note that GDAL
-  typically use a PixelIsArea convention (but can handle both conventions), so the
-  georeferencing it displays when opening a .gsb or .gtx file appears to have a 
-  half-pixel shift regarding to the coordinates stored in the original grid file. On
-  the reading side, PROJ will accept both conventions (for equivalent georeferencing,
-  the value of the origin in a PixelIsArea convention is shifted by a half-pixel
-  towards the upper-left direction). Unspecified behaviour if this GeoKey is absent.
-
-- Files hosted on the CDN will be tiled, presumably with 256x256 tiles (small
-  grids that are smaller than 256x256 will use a single strip). On the reading
-  side, PROJ will accept TIFF files with any strip or tile organization.
-  Tiling is expressed by specifying the TileWidth, TileHeight, TileOffsets
-  and TileByteCounts tags. Strip organization is expressed by specifying the
-  RowsPerStrip, StripByteCounts and StripOffsets tags.
-
-- Files hosted on the CDN will use `Compression
-  <https://www.awaresystems.be/imaging/tiff/tifftags/compression.html>`_ = DEFLATE
-  or LZW (to be determined, possibly with
-  `Predictor <https://www.awaresystems.be/imaging/tiff/tifftags/predictor.html>`_ = 2
-  or 3)
-  On the reading side, PROJ will accept TIFF files with any compression method
-  (appropriate for the data types and PhotometricInterpretation considered)
-  supported by the libtiff build used by PROJ. Of course uncompressed files will be supported.
-
-- Files hosted on the CDN will use little-endian byte ordering. On the reading
-  side, libtiff will transparently handle both little-endian and big-endian
-  ordering.
-
-- Files hosted on the CDN will use PlanarConfiguration=Separate.
-  The tools described in a later section will order blocks so that blocks needed
-  for a given location are close to each other.
-  On the reading side, PROJ will handle also PlanarConfiguration=Contig.
-
-- Files hosted on the CDN will generally use Float32 (BitsPerSample=32 and SampleFormat=IEEEFP)
-  Files may be created using Signed Int 16 (
-  `BitsPerSample <https://www.awaresystems.be/imaging/tiff/tifftags/bitspersample.html>`_ =16 and
-  `SampleFormat <https://www.awaresystems.be/imaging/tiff/tifftags/sampleformat.html>`_ = INT),
-  Unsigned Int 16 (BitsPerSample=16 and SampleFormat=UINT), Signed Int 32 or Unsigned Int 32 generally with an
-  associate scale/offset.
-  On the reading side, only those three data types will be supported as well.
-
-- Files hosted on the CDN will have a `PhotometricInterpretation
-  <https://www.awaresystems.be/imaging/tiff/tifftags/photometricinterpretation.html>`_ = MinIsBlack.
-  It will be assumed, and ignored on the reading side.
-
-- Files hosted on the CDN will nominally have:
-
-    * `SamplesPerPixel <https://www.awaresystems.be/imaging/tiff/tifftags/samplesperpixel.html>`_ = 2
-      for horizontal shift grid, with the first sample being the longitude offset
-      and the second sample being the latitude offset.
-
-    * SamplesPerPixel = 1 for vertical shift grids.
-
-   In the future, different values of SamplesPerPixel may be used to accomodate
-   for other needs. For example for deformation models, SamplesPerPixel = 3 to combine
-   horizontal and vertical adjustments.
-   And even for the current identified needs of horizontal or vertical shifts,
-   more samples may be present (to indicate for example uncertainties), but
-   will be ignored by PROJ.
-
-   The `ExtraSamples <https://www.awaresystems.be/imaging/tiff/tifftags/extrasamples.html>`_
-   tag should be set to a value of SamplesPerPixel - 1 (given the rules that
-   apply for PhotometricInterpretation = MinIsBlack)
-
-- The `ImageDescription <https://www.awaresystems.be/imaging/tiff/tifftags/imagedescription.html>`_
-  tag may be used to convey extra information about the name, provenance, version
-  and last updated date of the grid.
-  Will be set when possible fo files hosted on the CDN.
-  Ignored by PROJ.
-
-- The `Copyright <https://www.awaresystems.be/imaging/tiff/tifftags/copyright.html>`_
-  tag may be used to convey extra information about the copyright and license of the grid.
-  Will be set when possible fo files hosted on the CDN.
-  Ignored by PROJ.
-
-- The `DateTime <https://www.awaresystems.be/imaging/tiff/tifftags/datetime.html>`_
-  tag may be used to convey the date at which the file has been created or
-  converted. In case of a file conversion, for example from NTv2, this will be
-  the date at which the conversion has been performed. The ``ImageDescription``
-  tag however will contain the latest of the CREATED or UPDATED fields from the NTv2 file.
-  Will be set when possible fo files hosted on the CDN.
-  Ignored by PROJ.
-
-- Files hosted on the CDN will use the `GDAL_NODATA
-  <https://www.awaresystems.be/imaging/tiff/tifftags/gdal_nodata.html>`_ tag to encode
-  the value of the nodata / missing value, when it applies to the grid.
-
-  If offset and/or scaling is used, the nodata value corresponds to the raw value,
-  before applying offset and scaling.
-  The value found in this tag, if present, will be honoured (to the extent to
-  which current PROJ code makes use of nodata).
-  For floating point data, writers are strongly discouraged to use non-finite values
-  (+/- infinity, NaN) of nodata to maximimize interoperability.
-  The GDAL_NODATA value applies to all samples of a given TIFF IFD.
-
-- Files hosted on the CDN will use the `GDAL_METADATA
-  <https://www.awaresystems.be/imaging/tiff/tifftags/gdal_metadata.html>`_ tag to encode extra
-  metadata not supported by baseline or extended TIFF.
-
-  * The root XML node should be ``GDALMetadata``
-
-  * Zero, one or several child XML nodes ``Item`` may be present.
-
-  * A Item should have a ``name`` attribute, and a child text node with its value.
-    ``role`` and ``sample`` attributes may be present for attributes that have
-    a special semantics (recognized by GDAL). The value of `sample` should be
-    a integer value between 0 and number_of_samples - 1.
-
-  * Scale and offset to convert integer raw values to floating point values
-    may be expressed with XML `Item` elements whose name attribute is respectively
-    ``SCALE`` and ``OFFSET``, and their ``role`` attribute is respectively ``scale``
-    and ``offset``. The decoded value will be: {offset} + {scale} * raw_value_from_geotiff_file
-
-    For a offset value of 1 and scaling of 2, the following payload should be
-    stored:
-
-    .. code-block:: xml
-
-        <GDALMetadata>
-            <Item name="OFFSET" sample="0" role="offset">1</Item>
-            <Item name="SCALE" sample="0" role="scale">2</Item>
-        </GDALMetadata>
-
-  * The type of the grid must be specified with a `Item` whose ``name`` is set
-    to ``TYPE``.
-
-    Values recognized by PROJ currently are:
-
-    - ``HORIZONTAL_OFFSET``: implies the presence of at least two samples.
-      The first sample must contain the latitude offset and the second
-      sample must contain the longitude offset.
-      Corresponds to PROJ ``hgridshift`` method.
-
-    - ``VERTICAL_OFFSET_GEOGRAPHIC_TO_VERTICAL``: implies the presence of at least one sample.
-      The first sample must contain the vertical adjustment. Must be used when
-      the source/interpolation CRS is a Geographic CRS and the target CRS a Vertical CRS.
-      Corresponds to PROJ ``vgridshift`` method.
-
-    - ``VERTICAL_OFFSET_VERTICAL_TO_VERTICAL``: implies the presence of at least one sample.
-      The first sample must contain the vertical adjustment. Must be used when
-      the source and target CRS are Vertical CRS.
-      Corresponds to PROJ ``vgridshift`` method.
-
-    - ``GEOCENTRIC_TRANSLATION``: implies the presence of at least 3 samples.
-      The first 3 samples must be respectively the geocentric adjustments along
-      the X, Y and Z axis. Must be used when the source and target CRS are
-      geocentric CRS. The interpolation CRS must be a geographic CRS.
-      Corresponds to PROJ ``xyzgridshift`` method.
-
-    - ``VELOCITY``: implies the presence of at least 3 samples.
-      The first 3 samples must be respectively the velocities along
-      the E(ast), N(orth), U(p) axis in the local topocentric coordinate system.
-      Corresponds to PROJ ``deformation`` method.
-
-    For example:
-
-    .. code-block:: xml
-
-        <Item name="TYPE">HORIZONTAL_OFFSET</Item>
-
-  * The description of each sample must be specified with a Item whose ``name``
-    attribute is set to ``DESCRIPTION`` and ``role`` attribute to ``description``.
-
-    Values recognized by PROJ for this Item are currently:
-
-    + ``latitude_offset``: valid for TYPE=HORIZONTAL_OFFSET. Sample values should be
-      the value to add a latitude expressed in the CRS encoded in the GeoKeys
-      to obtain a latitude value expressed in the target CRS.
-
-    + ``longitude_offset``: valid for TYPE=HORIZONTAL_OFFSET. Sample values should be
-      the value to add a longitude expressed in the CRS encoded in the GeoKeys
-      to obtain a longitude value expressed in the target CRS.
-
-    + ``geoid_undulation``: valid for TYPE=VERTICAL_OFFSET_GEOGRAPHIC_TO_VERTICAL.
-      For a source CRS being a geographic CRS and a target CRS being a vertical CRS,
-      sample values should be the value to add to a geoid-related height (that
-      is expressed in the target CRS) to
-      get an ellipsoidal height (that is expressed in the source CRS), also
-      called the geoid undulation.
-      Note the possible confusion related to what is the source CRS and target CRS and
-      the semantics of the value stored (to convert from the source to the target,
-      one must subtract the value contained in the grid). This is the convention
-      used by the `EPSG:9665 <https://www.epsg-registry.org/export.htm?gml=urn:ogc:def:method:EPSG::9665>`_
-      operation method.
-
-    + ``vertical_offset``: valid for TYPE=VERTICAL_OFFSET_VERTICAL_TO_VERTICAL.
-      For a source and target CRS being vertical CRS,
-      sample values should be the value to add to an elevation expressed in the
-      source CRS to obtain a longitude value expressed in the target CRS.
-
-    + ``x_translation`` / ``y_translation`` / ``z_translation``: valid for
-      TYPE=GEOCENTRIC_TRANSLATION.
-      Sample values should be the value to add to the input geocentric coordinates
-      expressed in the source CRS to geocentric coordinates expressed in the target CRS.
-
-    + ``east_velocity`` / ``north_velocity`` / ``up_velocity``: valid for
-      TYPE=VELOCITY.
-      Sample values should be the velocity in a linear/time unit in a ENU local
-      topocentric coordinate system.
-
-    For example:
-
-    .. code-block:: xml
-
-        <Item name="DESCRIPTION" sample="0" role="description">latitude_offset</Item>
-        <Item name="DESCRIPTION" sample="1" role="description">longitude_offset</Item>
-
-    Other values may be used (not used by PROJ):
-
-    + ``latitude_offset_accuracy``: valid for TYPE=HORIZONTAL_OFFSET. Sample values should be
-      the accuracy of corresponding latitude_offset samples. Generally in metre (if converted from NTv2)
-
-    + ``longitude_offset_accuracy``: valid for TYPE=HORIZONTAL_OFFSET. Sample values should be
-      the accuracy of corresponding longitude_offset samples. Generally in metre (if converted from NTv2)
-
-  * The sign convention for the values of the ``longitude_offset`` channel
-    should be indicated with an Item named ``positive_value`` whose value
-    can be ``west`` or ``east``. NTv2 products originally use a ``west``
-    convention, but when converting from them to GeoTIFF, the sign of those
-    samples will be inverted so they use a more natural ``east`` convention.
-    If this item is absent, the default value is ``east``.
-
-  * The unit of the values stored in the grid must be specified for each
-    sample through an Item of name ``UNITTYPE`` and role ``unittype``
-    Valid values should be the name of entries from the EPSG ``unitofmeasure``
-    table. To maximize interoperability, writers are strongly encouraged to
-    limit themselves to the following values:
-
-    For linear units:
-
-    - ``metre`` (default value assumed if absent for vertical shift grid files, and value used for files stored on PROJ CDN)
-    - ``US survey foot``
-
-    For angular units:
-
-    - ``degree``
-    - ``arc-second`` (default value assumed if absent for longitude and latitude offset samples of horizontal shift grid files, and value used for files stored on PROJ CDN)
-
-    For velocity units:
-
-    - ``millimetres per year``
-
-    The longitude and latitude offset samples should use the same unit.
-    The geocentric translation samples should use the same unit.
-    The velocity samples should use the same unit.
-
-    Example:
-
-    .. code-block:: xml
-
-        <Item name="UNITTYPE" sample="0" role="unittype">arc-second</Item>
-        <Item name="UNITTYPE" sample="1" role="unittype">arc-second</Item>
-
-  * The ``target_crs_epsg_code`` metadata item should be present.
-    For a horizontal shift grid, this is the EPSG
-    code of the target geographic CRS. For a vertical shift grid, this is the
-    EPSG code of a the target vertical CRS.
-    If the target CRS has no associated EPSG code, ``target_crs_wkt`` must be
-    used.
-    Ignored by PROJ currently.
-
-  * The ``target_crs_wkt`` metadata item must be present if the
-    ``target_crs_epsg_code`` cannot be used.
-    Its value should be a valid WKT string according to
-    `WKT:2015 <http://docs.opengeospatial.org/is/12-063r5/12-063r5.html>`_
-    or `WKT:2019 <hhttp://docs.opengeospatial.org/is/18-010r7/18-010r7.html>`_
-    Ignored by PROJ currently.
-
-  * The ``source_crs_epsg_code`` metadata item must be present if the source
-    and interpolation CRS are not the same (typical use case is vertical CRS to vertical CRS
-    transformation), because the GeoKeys encode the interpolation CRS and not the source CRS.
-    If the source CRS has no associated EPSG code, ``source_crs_wkt`` must be
-    used.
-    Ignored by PROJ currently.
-
-  * The ``source_crs_wkt`` metadata item must be present if the
-    ``source_crs_epsg_code`` cannot be used.
-    Its value should be a valid WKT string according to WKT:2015 or WKT:2019.
-    Ignored by PROJ currently.
-
-  * The ``interpolation_crs_wkt`` metadata item may be present if the GeoKeys
-    cannot be used to express reliably the interpolation CRS.
-    Its value should be a valid WKT string according to WKT:2015 or WKT:2019.
-    Ignored by PROJ currently.
-
-  * The ``recommended_interpolation_method`` metadata item may be present to
-    describe the method to use to interpolation values at locations not
-    coincident with nodes stored in the grid file. Potential values: ``bilinear``,
-    ``bicubic``.
-    Ignored by PROJ currently.
-
-  * The ``area_of_use`` metadata item can be used to indicate plain text information
-    about the area of use of the grid (like "USA - Wisconsin"). In case of multiple
-    subgrids, it should be set only on the first one, but applies to the whole
-    set of grids, not just the first one.
-
-  * The ``grid_name`` metadata item should be present if there are
-    subgrids for this grid (that is grids whose extent is contained in the extent
-    of this grid), or if this is a subgrid.
-    It is intended to be a relatively short identifier
-    Will be ignored by PROJ (this information can be inferred by the grids extent)
-
-  * The ``parent_grid_name`` metadata item should be present if this is a
-    subgrid and its value should be equal to the paren's ``grid_name``
-    Will be ignored by PROJ (this information can be inferred by the grids extent)
-
-  * The ``number_of_nested_grids`` metadata item should be present if there are
-    subgrids for this grid (that is grids whose extent is contained in the extent
-    of this grid).
-    Will be ignored by PROJ (this information can be inferred by the grids extent)
-
-Example
-+++++++
-
-https://github.com/rouault/sample_proj_gtiff_grids/blob/master/ntf_r93.tif has
-been converted from https://github.com/OSGeo/proj-datumgrid/blob/master/ntf_r93.gsb
-with https://github.com/rouault/sample_proj_gtiff_grids/blob/master/ntv2_to_gtiff.py
-
-::
-
-    $ tiffinfo ntf_r93.tif 
-
-    TIFF Directory at offset 0x4e (78)
-    Image Width: 156 Image Length: 111
-    Bits/Sample: 32
-    Sample Format: IEEE floating point
-    Compression Scheme: AdobeDeflate
-    Photometric Interpretation: min-is-black
-    Extra Samples: 3<unspecified, unspecified, unspecified>
-    Samples/Pixel: 4
-    Rows/Strip: 111
-    Planar Configuration: separate image planes
-    ImageDescription: NTF (EPSG:4275) to RGF93 (EPSG:4171). Converted from ntf_r93.gsb (version IGN07_01, last updated on 2007-10-31)
-    DateTime: 2019:12:09 00:00:00
-    Copyright: Derived from work by IGN France. Open License https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf
-    Tag 33550: 0.100000,0.100000,0.000000
-    Tag 33922: 0.000000,0.000000,0.000000,-5.500000,52.000000,0.000000
-    Tag 34735: 1,1,1,3,1024,0,1,2,1025,0,1,2,2048,0,1,4275
-    Tag 42112: <GDALMetadata>
-    <Item name="grid_name">FRANCE</Item>
-    <Item name="target_crs_epsg_code">4171</Item>
-    <Item name="TYPE">HORIZONTAL_OFFSET</Item>
-    <Item name="UNITTYPE" sample="0" role="unittype">arc-second</Item>
-    <Item name="DESCRIPTION" sample="0" role="description">latitude_offset</Item>
-    <Item name="positive_value" sample="1">east</Item>
-    <Item name="UNITTYPE" sample="1" role="unittype">arc-second</Item>
-    <Item name="DESCRIPTION" sample="1" role="description">longitude_offset</Item>
-    <Item name="UNITTYPE" sample="2" role="unittype">arc-second</Item>
-    <Item name="DESCRIPTION" sample="2" role="description">latitude_offset_accuracy</Item>
-    <Item name="UNITTYPE" sample="3" role="unittype">arc-second</Item>
-    <Item name="DESCRIPTION" sample="3" role="description">longitude_offset_accuracy</Item>
-    </GDALMetadata>
-
-    Predictor: floating point predictor 3 (0x3)
-
-
-::
-
-    $ listgeo ntf_r93.tif 
-
-    Geotiff_Information:
-        Version: 1
-        Key_Revision: 1.1
-        Tagged_Information:
-            ModelTiepointTag (2,3):
-                0                 0                 0                
-                -5.5              52                0                
-            ModelPixelScaleTag (1,3):
-                0.1               0.1               0                
-            End_Of_Tags.
-        Keyed_Information:
-            GTModelTypeGeoKey (Short,1): ModelTypeGeographic
-            GTRasterTypeGeoKey (Short,1): RasterPixelIsPoint
-            GeodeticCRSGeoKey (Short,1): Code-4275 (NTF)
-            End_Of_Keys.
-        End_Of_Geotiff.
-
-    GCS: 4275/NTF
-    Datum: 6275/Nouvelle Triangulation Francaise
-    Ellipsoid: 7011/Clarke 1880 (IGN) (6378249.20,6356515.00)
-    Prime Meridian: 8901/Greenwich (0.000000/  0d 0' 0.00"E)
-    Projection Linear Units: User-Defined (1.000000m)
-
-    Corner Coordinates:
-    Upper Left    (  5d30' 0.00"W, 52d 0' 0.00"N)
-    Lower Left    (  5d30' 0.00"W, 40d54' 0.00"N)
-    Upper Right   ( 10d 6' 0.00"E, 52d 0' 0.00"N)
-    Lower Right   ( 10d 6' 0.00"E, 40d54' 0.00"N)
-    Center        (  2d18' 0.00"E, 46d27' 0.00"N)
-
-::
-
-    $ gdalinfo ntf_r93.tif
-
-    Driver: GTiff/GeoTIFF
-    Files: ntf_r93.tif
-    Size is 156, 111
-    Coordinate System is:
-    GEOGCRS["NTF",
-        DATUM["Nouvelle Triangulation Francaise",
-            ELLIPSOID["Clarke 1880 (IGN)",6378249.2,293.466021293627,
-                LENGTHUNIT["metre",1]]],
-        PRIMEM["Greenwich",0,
-            ANGLEUNIT["degree",0.0174532925199433]],
-        CS[ellipsoidal,2],
-            AXIS["geodetic latitude (Lat)",north,
-                ORDER[1],
-                ANGLEUNIT["degree",0.0174532925199433]],
-            AXIS["geodetic longitude (Lon)",east,
-                ORDER[2],
-                ANGLEUNIT["degree",0.0174532925199433]],
-        ID["EPSG",4275]]
-    Data axis to CRS axis mapping: 2,1
-    Origin = (-5.550000000000000,52.049999999999997)
-    Pixel Size = (0.100000000000000,-0.100000000000000)
-    Metadata:
-      AREA_OR_POINT=Point
-      grid_name=FRANCE
-      target_crs_epsg_code=4171
-      TIFFTAG_DATETIME=2019:12:09 00:00:00
-      TIFFTAG_IMAGEDESCRIPTION=NTF (EPSG:4275) to RGF93 (EPSG:4171). Converted from ntf_r93.gsb (version IGN07_01, last updated on 2007-10-31)
-      TYPE=HORIZONTAL_OFFSET
-    Image Structure Metadata:
-      COMPRESSION=DEFLATE
-      INTERLEAVE=BAND
-    Corner Coordinates:
-    Upper Left  (  -5.5500000,  52.0500000) (  5d33' 0.00"W, 52d 3' 0.00"N)
-    Lower Left  (  -5.5500000,  40.9500000) (  5d33' 0.00"W, 40d57' 0.00"N)
-    Upper Right (  10.0500000,  52.0500000) ( 10d 3' 0.00"E, 52d 3' 0.00"N)
-    Lower Right (  10.0500000,  40.9500000) ( 10d 3' 0.00"E, 40d57' 0.00"N)
-    Center      (   2.2500000,  46.5000000) (  2d15' 0.00"E, 46d30' 0.00"N)
-    Band 1 Block=156x111 Type=Float32, ColorInterp=Gray
-      Description = latitude_offset
-      Unit Type: arc-second
-    Band 2 Block=156x111 Type=Float32, ColorInterp=Undefined
-      Description = longitude_offset
-      Unit Type: arc-second
-      Metadata:
-        positive_value=east
-    Band 3 Block=156x111 Type=Float32, ColorInterp=Undefined
-      Description = latitude_offset_accuracy
-      Unit Type: arc-second
-    Band 4 Block=156x111 Type=Float32, ColorInterp=Undefined
-      Description = longitude_offset_accuracy
-      Unit Type: arc-second
-
-Multi-grid storage
+Format description
 ++++++++++++++++++
 
-Formats like NTv2 can contain multiple subgrids. This can be transposed to
-TIFF by using several IFD chained together with the last 4 bytes (or 8 bytes
-for BigTIFF) of an IFD pointing to the offset of the next one.
-
-The first IFD should have a full description according to the
-:ref:`Description of the PROJ GeoTIFF format <description_geotiff_format>`.
-Subsequent IFD might have a more compact description, omitting for example, CRS
-information if it is identical to the main IFD (which should be the case for
-the currently envisionned use cases), or Copyright / ImageDescription metadata
-items.
-
-Each IFD will have its
-`NewSubfileType <https://www.awaresystems.be/imaging/tiff/tifftags/newsubfiletype.html>`_
-tag set to 0.
-
-If a low-resolution grid is available, it should be put before subgrids of
-higher-resolution in the chain of IFD linking. On reading, PROJ will use the
-value from the highest-resoluted grid that contains the point of interest.
-
-For efficient reading from the network, files hosted on the CDN will use
-a layout similar to the one described in the `low level paragraph of the Cloud Optimized GeoTIFF
-GDAL driver page <https://gdal.org/drivers/raster/cog.html#low-level>`_
-
-The layout for a file converted from NTv2 will for example be:
-
-- TIFF/BigTIFF header/signature and pointer to first IFD (Image File Directory)
-- "ghost area" indicating the generated process
-- IFD of the first grid, followed by TIFF tags values, excluding the TileOffsets and TileByteCounts arrays
-- ...
-- IFD of the last grid, followed by TIFF tags values, excluding the GDAL_METADATA tag, TileOffsets and TileByteCounts arrays
-- TileOffsets and TileByteCounts arrays for first IFD
-- ...
-- TileOffsets and TileByteCounts arrays for last IFD
-- Value of GDAL_METADATA tag for IFDs following the first IFD
-- First IFD: Data corresponding to latitude offset of Block_0_0
-- First IFD: Data corresponding to longitude offset of Block_0_0
-- First IFD: Data corresponding to latitude offset of Block_0_1
-- First IFD: Data corresponding to longitude offset of Block_0_1
-- ...
-- First IFD: Data corresponding to latitude offset of Block_n_m
-- First IFD: Data corresponding to longitude offset of Block_n_m
-- ...
-- Last IFD: Data corresponding to latitude offset of Block_0_0
-- Last IFD: Data corresponding to longitude offset of Block_0_0
-- Last IFD: Data corresponding to latitude offset of Block_0_1
-- Last IFD: Data corresponding to longitude offset of Block_0_1
-- ...
-- Last IFD: Data corresponding to latitude offset of Block_n_m
-- Last IFD: Data corresponding to longitude offset of Block_n_m
-
-If longitude_offset_accuracy and latitude_offset_accuracy are present, this
-will be followed by:
-
-- First IFD: Data corresponding to latitude offset accuracy of Block_0_0
-- First IFD: Data corresponding to longitude offset accuracy of Block_0_0
-- ...
-- First IFD: Data corresponding to latitude offset accuracy of Block_n_m
-- First IFD: Data corresponding to longitude offset accuracy of Block_n_m
-- ...
-- Last IFD: Data corresponding to latitude offset accuracy of Block_0_0
-- Last IFD: Data corresponding to longitude offset accuracy of Block_0_0
-- ...
-- Last IFD: Data corresponding to latitude offset accuracy of Block_n_m
-- Last IFD: Data corresponding to longitude offset accuracy of Block_n_m
-
-.. note::
-
-    TIFF has another mechanism to link IFDs, the SubIFD tag. This potentially
-    enables to define a hiearchy of IFDs (similar to HDF5 groups). There is no
-    support for that in most TIFF-using software, notably GDAL, and no compelling
-    need to have a nested hiearchy, so "flat" organization with the standard IFD chaining
-    mechanism is adopted.
-
-Examples of multi-grid dataset
-++++++++++++++++++++++++++++++
-
-https://github.com/rouault/sample_proj_gtiff_grids/blob/master/GDA94_GDA2020_conformal.tif has
-been converted from https://github.com/OSGeo/proj-datumgrid/blob/master/oceania/GDA94_GDA2020_conformal.gsb
-with https://github.com/rouault/sample_proj_gtiff_grids/blob/master/ntv2_to_gtiff.py
-
-It contains 5 subgrids. All essential metadata to list the subgrids and their
-georeferencing is contained within the first 3 KB of the file.
-
-The file size is 4.8 MB using DEFLATE compression and floating-point predictor.
-To be compared with the 83 MB of the original .gsb file.
-
-https://github.com/rouault/sample_proj_gtiff_grids/blob/master/ntv2_0.tif  has
-been converted from https://github.com/OSGeo/proj-datumgrid/blob/master/north-america/ntv2_0.gsb
-
-It contains 114 subgrids. All essential metadata to list the subgrids and their
-georeferencing is contained within the first 40 KB of the file.
-
+The format description is available in a dedicated :ref:`geodetictiffgrids`
+document.
 
 Tooling
 +++++++

docs/source/conf.py

@@ -376,7 +376,7 @@ texinfo_documents = [
 #texinfo_no_detailmenu = False
 
 breathe_projects = {
-    "cpp_stuff":"../build/xml/",
+    "doxygen_api":"../build/xml/",
 }
 
 import redirects

docs/source/development/reference/cpp/common.rst

@@ -4,5 +4,5 @@ common namespace
 ----------------
 
 .. doxygennamespace:: osgeo::proj::common
-   :project: cpp_stuff
+   :project: doxygen_api
    :members:

docs/source/development/reference/cpp/cpp_general.rst

@@ -4,4 +4,4 @@ General documentation
 ---------------------
 
 .. doxygenfile:: general_doc.dox.reworked.h
-   :project: cpp_stuff
+   :project: doxygen_api

docs/source/development/reference/cpp/crs.rst

@@ -4,5 +4,5 @@ crs namespace
 -------------
 
 .. doxygennamespace:: osgeo::proj::crs
-   :project: cpp_stuff
+   :project: doxygen_api
    :members:

docs/source/development/reference/cpp/cs.rst

@@ -4,5 +4,5 @@ cs namespace
 ------------
 
 .. doxygennamespace:: osgeo::proj::cs
-   :project: cpp_stuff
+   :project: doxygen_api
    :members:

docs/source/development/reference/cpp/datum.rst

@@ -4,5 +4,5 @@ datum namespace
 ---------------
 
 .. doxygennamespace:: osgeo::proj::datum
-   :project: cpp_stuff
+   :project: doxygen_api
    :members:

docs/source/development/reference/cpp/io.rst

@@ -4,5 +4,5 @@ io namespace
 ------------
 
 .. doxygennamespace:: osgeo::proj::io
-   :project: cpp_stuff
+   :project: doxygen_api
    :members:

docs/source/development/reference/cpp/metadata.rst

@@ -4,5 +4,5 @@ metadata namespace
 ------------------
 
 .. doxygennamespace:: osgeo::proj::metadata
-   :project: cpp_stuff
+   :project: doxygen_api
    :members:

docs/source/development/reference/cpp/operation.rst

@@ -4,5 +4,5 @@ operation namespace
 -------------------
 
 .. doxygennamespace:: osgeo::proj::operation
-   :project: cpp_stuff
+   :project: doxygen_api
    :members:

docs/source/development/reference/cpp/util.rst

@@ -4,5 +4,5 @@ util namespace
 --------------
 
 .. doxygennamespace:: osgeo::proj::util
-   :project: cpp_stuff
+   :project: doxygen_api
    :members:

docs/source/development/reference/datatypes.rst

@@ -797,11 +797,48 @@ Logging
     .. versionadded:: 5.1.0
 
 
+Setting custom I/O functions
+-------------------------------------------------------------------------------
+
+.. versionadded:: 7.0.0
+
+.. doxygenstruct:: PROJ_FILE_API
+   :project: doxygen_api
+   :members:
+
+.. doxygentypedef:: PROJ_FILE_HANDLE
+   :project: doxygen_api
+
+.. doxygenenum:: PROJ_OPEN_ACCESS
+   :project: doxygen_api
+
+
+Network related functionality
+-------------------------------------------------------------------------------
+
+.. versionadded:: 7.0.0
+
+.. doxygentypedef:: PROJ_NETWORK_HANDLE
+   :project: doxygen_api
+
+.. doxygentypedef:: proj_network_open_cbk_type
+   :project: doxygen_api
+
+.. doxygentypedef:: proj_network_close_cbk_type
+   :project: doxygen_api
+
+.. doxygentypedef:: proj_network_get_header_value_cbk_type
+   :project: doxygen_api
+
+.. doxygentypedef:: proj_network_read_range_type
+   :project: doxygen_api
+
+
 C API for ISO-19111 functionality
 -------------------------------------------------------------------------------
 
 .. doxygengroup:: iso19111_types
-   :project: cpp_stuff
+   :project: doxygen_api
    :content-only:
 
 

docs/source/development/reference/functions.rst

@@ -697,6 +697,54 @@ Various
     :returns: :c:type:`int` 1 if output units is expected in radians, otherwise 0
 
 
+Setting custom I/O functions
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+.. versionadded:: 7.0.0
+
+.. doxygenfunction:: proj_context_set_fileapi
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_context_set_sqlite3_vfs_name
+   :project: doxygen_api
+
+
+Network related functionality
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+.. versionadded:: 7.0.0
+
+.. doxygenfunction:: proj_context_set_network_callbacks
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_context_set_enable_network
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_context_set_url_endpoint
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_grid_cache_set_enable
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_grid_cache_set_filename
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_grid_cache_set_max_size
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_grid_cache_set_ttl
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_grid_cache_clear
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_is_download_needed
+   :project: doxygen_api
+
+.. doxygenfunction:: proj_download_file
+   :project: doxygen_api
+
+
 Cleanup
 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
@@ -727,6 +775,6 @@ which are not of type CRS (can be tested with :c:func:`proj_is_crs`),
 will return an error when used with functions of this section.
 
 .. doxygengroup:: iso19111_functions
-   :project: cpp_stuff
+   :project: doxygen_api
    :content-only:
 

docs/source/index.rst

@@ -17,6 +17,7 @@ PROJ
    resource_files
    geodesic
    development/index
+   specifications/index
    community/index
    faq
    glossary

docs/source/operations/transformations/deformation.rst

@@ -35,6 +35,9 @@ GTX format. Both grids are expected to contain grid-values in units of
 mm/year. GDAL both reads and writes both file formats. Using GDAL for
 construction of new grids is recommended.
 
+Starting with PROJ 7.0, use of a GeoTIFF format is recommended to store both
+the horizontal and vertical velocities.
+
 Example
 -------------------------------------------------------------------------------
 
@@ -89,13 +92,15 @@ Parameters
 
 .. option:: +xy_grids=<list>
 
-    Comma-separated list of grids to load. If a grid is prefixed by an `@` the
+    Comma-separated list of grids to load. If a grid is prefixed by an ``@`` the
     grid is considered optional and PROJ will the not complain if the grid is
     not available.
 
-    Grids for the horizontla component of a deformation model is expected to be
+    Grids for the horizontal component of a deformation model is expected to be
     in CTable2 format.
 
+    .. note:: :option:`+xy_grids` is mutually exclusive with :option:`+grids`
+
 .. option:: +z_grids=<list>
 
     Comma-separated list of grids to load. If a grid is prefixed by an `@` the
@@ -105,6 +110,36 @@ Parameters
     Grids for the vertical component of a deformation model is expected to be
     in either GTX format.
 
+    .. note:: :option:`+z_grids` is mutually exclusive with :option:`+grids`
+
+.. option:: +grids=<list>
+
+    .. versionadded:: 7.0.0
+
+    Comma-separated list of grids to load. If a grid is prefixed by an `@` the
+    grid is considered optional and PROJ will the not complain if the grid is
+    not available.
+
+    Grids should be in GeoTIFF format with the first 3 components being
+    respectively the easting, northing and up velocities in mm/year.
+    Setting the Description and Unit Type GDAL band metadata items is strongly
+    recommended, so that gdalinfo reports:
+
+    ::
+
+        Band 1 Block=... Type=Float32, ColorInterp=Gray
+            Description = east_velocity
+            Unit Type: mm/year
+        Band 2 Block=... Type=Float32, ColorInterp=Undefined
+            Description = north_velocity
+            Unit Type: mm/year
+        Band 3 Block=... Type=Float32, ColorInterp=Undefined
+            Description = up_velocity
+            Unit Type: mm/year
+
+    .. note:: :option:`+grids` is mutually exclusive with :option:`+xy_grids`
+              and :option:`+z_grids`
+
 .. option:: +t_epoch=<value>
 
     Central epoch of transformation given in decimalyears. Will be used in

docs/source/operations/transformations/index.rst

@@ -19,3 +19,4 @@ systems are based on different datums.
    molobadekas
    hgridshift
    vgridshift
+   xyzgridshift

docs/source/operations/transformations/xyzgridshift.rst

@@ -0,0 +1,91 @@
+.. _xyzgridshift:
+
+================================================================================
+Geocentric grid shift
+================================================================================
+
+.. versionadded:: 7.0.0
+
+Geocentric translation using a grid shift
+
++-----------------+-------------------------------------------------------------------+
+| **Domain**      | 3D                                                                |
++-----------------+-------------------------------------------------------------------+
+| **Input type**  | Cartesian coordinates                                             |
++-----------------+-------------------------------------------------------------------+
+| **Output type** | Cartesian coordinates                                             |
++-----------------+-------------------------------------------------------------------+
+
+Perform a geocentric translation by bilinear interpolation of dx, dy, dz
+translation values from a grid. The grid is referenced against either the
+2D geographic CRS corresponding to the input (or sometimes output) CRS.
+
+This method is described (in French) in :cite:`NTF_88`
+and as EPSG operation method code 9655 in :cite:`IOGP2018` (§2.4.4.1.1
+France geocentric interpolation).
+
+The translation in the grids are added to the input coordinates in the forward direction,
+and subtracted in the reverse direction.
+By default (if ``grid_ref=input_crs``), in the forward direction, the input coordinates
+are converted to their geographic equivalent to directly read and interpolate from
+the grid. In the reverse direction, an iterative method is used to be able to find
+the grid locations to read.
+If ``grid_ref=output_crs`` is used, then the reverse strategy is applied: iterative
+method in the forward direction, and direct read in the reverse direction.
+
+Example
+-------------------------------------------------------------------------------
+
+NTF to RGF93 transformation using gr3df97a.tif grid
+
+::
+
+    +proj=pipeline
+        +step +proj=push +v_3
+        +step +proj=cart +ellps=clrk80ign
+        +step +proj=xyzgridshift +grids=gr3df97a.tif +grid_ref=output_crs +ellps=GRS80
+        +step +proj=cart +ellps=GRS80 +inv
+        +step +proj=pop +v_3
+
+Parameters
+################################################################################
+
+The ellipsoid parameters should be the ones consistent with ``grid_ref``.
+They are used to perform a geocentric to geographic conversion to find the
+translation parameters.
+
+
+Required
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+.. include:: ../options/ellps.rst
+
+.. option:: +grids=<list>
+
+    Comma-separated list of grids to load. If a grid is prefixed by an ``@`` the
+    grid is considered optional and PROJ will the not complain if the grid is
+    not available.
+
+    Grids are expected to be in GeoTIFF format. If no metadata is provided,
+    the first, second and third samples are assumed to be the geocentric
+    translation along X, Y and Z axis respectively, in metres.
+
+Optional
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+.. option:: +grid_ref=input_crs/output_crs
+
+    Specify in which CRS the grid is referenced to. The default value is
+    input_crs. That is the grid is referenced in the geographic CRS corresponding
+    to the input geocentric CRS.
+
+    If output_crs is specified, the grid is referenced in the geographic CRS corresponding
+    to the output geocentric CRS. This is for example the case for the French
+    gr3df97a.tif grid converting from NTF to RGF93, but referenced against RGF93.
+    Thus in the forward direction (NTF->RGF93), an iterative method is used to find
+    the appropriate shift.
+
+.. option:: +multiplier=<value>
+
+    Specify the multiplier to apply to the grid values. Defaults to 1.0
+

docs/source/references.bib

@@ -229,6 +229,15 @@
   Doi                      = {10.2312/PE/PG/PG2012short/005-010}
 }
 
+@TechReport{NTF_88,
+  Title                    = {Grille de parametres de transformation de coordonnees - {GR3DF97A} - Notice d'utilisation},
+  Author                   = {IGN},
+  Institution              = {Service de Geodesie et Nivellement, Institut Geographique National},
+  Year                     = {1997},
+
+  Url                      = {https://geodesie.ign.fr/contenu/fichiers/documentation/algorithmes/notice/NTG_88.pdf}
+}
+
 @TechReport{ONeilLaubscher1976,
   Title                    = {Extended Studies of a Quadrilateralized Spherical Cube Earth Data Base},
   Author                   = {E. M. O'Neill and R. E. Laubscher},

docs/source/resource_files.rst

@@ -14,6 +14,8 @@ In addition to the bundled init-files the PROJ project also distributes a number
 of packages containing transformation grids and additional init-files not included
 in the main PROJ package.
 
+.. _resource_file_paths:
+
 Where are PROJ resource files looked for ?
 -------------------------------------------------------------------------------
 
@@ -23,23 +25,43 @@ The following paths are checked in order:
 
 - For transformation grids that have an explict relative or absolute path,
   the directory specified in the grid filename.
+
 - Path resolved by the callback function set with
   the :c:func:`proj_context_set_file_finder`. If it is set, the next tests
   will not be run.
+
 - Path(s) set with the :c:func:`proj_context_set_search_paths`. If set, the
   next tests will not be run.
+
+.. _user_writable_directory:
+
+- The PROJ user writable directory, which is :
+
+    * on Windows, ${LOCALAPPDATA}/proj
+    * on MacOSX, ${HOME}/Library/Application Support/proj
+    * on other platforms (Linux), ${XDG_DATA_HOME}/proj if :envvar:`XDG_DATA_HOME`
+      is defined. Else ${HOME}/.local/share/proj
+
 - Path(s) set with by the environment variable :envvar:`PROJ_LIB`.
   On Linux/MacOSX/Unix, use ``:`` to separate paths. On Windows, ``;``
+
 - On Windows, the *..\\share\\proj\\* and its contents are found automatically
   at run-time if the installation respects the build structure. That is, the
   binaries and proj.dll are installed under *..\\bin\\*, and resource files
   are in *..\\share\\proj\\*.
+
 - A path built into PROJ as its resource installation directory (whose value is
   $(pkgdatadir)), for builds using the Makefile build system. Note, however,
   that since this is a hard-wired path setting, it only works if the whole
   PROJ installation is not moved somewhere else.
+
 - The current directory
 
+When networking capabilities are enabled, either by API with the
+:c:func:`proj_context_set_enable_network` function or when the
+:envvar:`PROJ_NETWORK` environment variable is set to ``ON``, PROJ will
+attempt to use remote grids stored on CDN (Content Delivery Network) storage.
+
 .. _proj-db:
 
 proj.db
@@ -49,6 +71,38 @@ A proj installation includes a SQLite database of transformation information
 that must be accessible for the library to work properly.  The library will
 print an error if the database can't be found.
 
+.. _proj-ini:
+
+proj.ini
+-------------------------------------------------------------------------------
+
+.. versionadded:: 7.0
+
+proj.ini is a text configuration file, mostly dedicated at setting up network
+related parameters.
+
+Its default content is:
+
+::
+
+    [general]
+    ; Lines starting by ; are commented lines.
+    ;
+
+    ; Network capabilities disabled by default.
+    ; Can be overriden with the PROJ_NETWORK=ON environment variable.
+    ; network = on
+
+    ; Can be overriden with the PROJ_NETWORK_ENDPOINT environment variable.
+    cdn_endpoint = https://cdn.proj.org
+
+    cache_enabled = on
+
+    cache_size_MB = 300
+
+    cache_ttl_sec = 86400
+
+
 Transformation grids
 -------------------------------------------------------------------------------
 

docs/source/specifications/geodetictiffgrids.rst

@@ -0,0 +1,626 @@
+.. _geodetictiffgrids:
+
+================================================================================
+Geodetic TIFF grids (GTG)
+================================================================================
+
+.. versionadded:: 7.0
+
+Introduction
+++++++++++++
+
+The Geodetic TIFF grid format has been introduced per :ref:`rfc4`. It is a
+profile of the TIFF and GeoTIFF formats that addresses the specific requirements
+of geodetic grids: horizontal shifts, vertical shifts, velocity grids, etc...
+It also follows the `Cloud Optimized GeoTIFF <http://cogeo.org>`_ principles.
+
+Such grids are available on a :ref:`CDN of GeoTIFF grids <cdn_grids>`.
+
+.. _gtg_general_description:
+
+General description
++++++++++++++++++++
+
+The general principles that guide the following requirements and recommendations
+are such that files will be properly recognized by PROJ, and also by GDAL which
+is an easy way to inspect such grid files:
+
+- `TIFF 6.0 <https://www.awaresystems.be/imaging/tiff/specification/TIFF6.pdf>`_
+  based (could possibly be BigTIFF without code changes, if we ever
+  need some day to handle grids larger than 4GB)
+
+- `GeoTIFF 1.1 <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html>`_ for the georeferencing.
+  GeoTIFF 1.1 is a recent standard, compared to the original GeoTIFF 1.0 version,
+  but its backward compatibility is excellent, so that should not cause much trouble
+  to readers that are not official GeoTIFF 1.1 compliant.
+
+- Files hosted on the CDN will use a Geographic 2D CRS for the GeoTIFF GeoKeys.
+  That CRS is intended to be the interpolation CRS as defined in
+  `OGC Abstract Specification Topic 2 <http://docs.opengeospatial.org/as/18-005r4/18-005r4.html>`_,
+  that is the CRS to which grid values are refered to.
+
+  Given that they will nominally be related to the EPSG dataset, the `GeodeticCRSGeoKey
+  <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html#_requirements_class_geodeticcrsgeokey>`_
+  will be used to store the EPSG code of the CRS. If the CRS cannot be reliably
+  encoded through that key or other geokeys, the ``interpolation_crs_wkt`` metadata
+  item detailed afterwards should be used.
+
+  This CRS will be generally the source CRS (for geographic to
+  geographic horizontal shift grids, or geographic to vertical shift grids), but
+  for vertical to vertical CRS adjustment, this will be the geographic CRS to
+  which the grid is referenced. In some very rare cases of geographic to vertical
+  shift grids, the interpolation CRS might be a geographic CRS that is not the
+  same as the source CRS (into which ellipsoidal height are expressed). The only
+  instance we have in mind is for the EPSG:7001 "ETRS89 to NAP height (1)" transformation
+  using the naptrans2008 VDatum-grid which is referenced to Amersfoort EPSG:4289
+  instead of ETRS89...
+
+  On the reading side, PROJ will ignore that information:
+  the CRS is already stored in the source_crs or interpolation_crs column of the
+  grid_transformation table.
+
+  For geographic to vertical shift files (geoid models), the GeoTIFF 1.1
+  convention will be used to store the value of the `VerticalGeoKey
+  <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html#_requirements_class_verticalgeokey>`_
+  So a geoid model that apply to WGS 84 EPSG:4979 will have GeodeticCRSGeoKey = 4326
+  and VerticalGeoKey = 4979.
+
+- Files hosted on the CDN will use the GeoTIFF defined `ModelTiepointTag and ModelPixelScaleTag
+  <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html#_raster_to_model_coordinate_transformation_requirements>`_ TIFF tags
+  to store the coordinates of the upper-left pixel and the resolution of the pixels.
+  On the reading side, they will be required and ModelTransformationTag will be ignored.
+
+  .. note::
+
+    Regarding anti-meridian handling, a variety of possibilities exist.
+    We do not attempt to standardize this and filesh hosted on the CDN will use
+    a georeferencing close to the original data producer.
+    For example, NOAA vertical grids that apply to Conterminous USA might even have a top-left
+    longitude beyond 180 (for consistency with Alaska grids, whose origin is < 180)
+    Anti-meridian handling in PROJ has probably issues. This RFC does not attempt
+    to address them in particular, as they are believed to be orthogonal to the
+    topics it covers, and being mostly implementation issues.
+
+- Files hosted on the CDN will use the `GTRasterTypeGeoKey
+  <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html#_requirements_class_gtrastertypegeokey>`_
+  = PixelIsPoint convention.
+  This is the convention used by most existing grid formats currently. Note that GDAL
+  typically use a PixelIsArea convention (but can handle both conventions), so the
+  georeferencing it displays when opening a .gsb or .gtx file appears to have a 
+  half-pixel shift regarding to the coordinates stored in the original grid file. On
+  the reading side, PROJ will accept both conventions (for equivalent georeferencing,
+  the value of the origin in a PixelIsArea convention is shifted by a half-pixel
+  towards the upper-left direction). Unspecified behaviour if this GeoKey is absent.
+
+- Files hosted on the CDN will be tiled, presumably with 256x256 tiles (small
+  grids that are smaller than 256x256 will use a single strip). On the reading
+  side, PROJ will accept TIFF files with any strip or tile organization.
+  Tiling is expressed by specifying the TileWidth, TileHeight, TileOffsets
+  and TileByteCounts tags. Strip organization is expressed by specifying the
+  RowsPerStrip, StripByteCounts and StripOffsets tags.
+
+- Files hosted on the CDN will use `Compression
+  <https://www.awaresystems.be/imaging/tiff/tifftags/compression.html>`_ = DEFLATE
+  or LZW (to be determined, possibly with
+  `Predictor <https://www.awaresystems.be/imaging/tiff/tifftags/predictor.html>`_ = 2
+  or 3)
+  On the reading side, PROJ will accept TIFF files with any compression method
+  (appropriate for the data types and PhotometricInterpretation considered)
+  supported by the libtiff build used by PROJ. Of course uncompressed files will be supported.
+
+- Files hosted on the CDN will use little-endian byte ordering. On the reading
+  side, libtiff will transparently handle both little-endian and big-endian
+  ordering.
+
+- Files hosted on the CDN will use PlanarConfiguration=Separate.
+  The tools described in a later section will order blocks so that blocks needed
+  for a given location are close to each other.
+  On the reading side, PROJ will handle also PlanarConfiguration=Contig.
+
+- Files hosted on the CDN will generally use Float32 (BitsPerSample=32 and SampleFormat=IEEEFP)
+  Files may be created using Signed Int 16 (
+  `BitsPerSample <https://www.awaresystems.be/imaging/tiff/tifftags/bitspersample.html>`_ =16 and
+  `SampleFormat <https://www.awaresystems.be/imaging/tiff/tifftags/sampleformat.html>`_ = INT),
+  Unsigned Int 16 (BitsPerSample=16 and SampleFormat=UINT), Signed Int 32 or Unsigned Int 32 generally with an
+  associate scale/offset.
+  On the reading side, only those three data types will be supported as well.
+
+- Files hosted on the CDN will have a `PhotometricInterpretation
+  <https://www.awaresystems.be/imaging/tiff/tifftags/photometricinterpretation.html>`_ = MinIsBlack.
+  It will be assumed, and ignored on the reading side.
+
+- Files hosted on the CDN will nominally have:
+
+    * `SamplesPerPixel <https://www.awaresystems.be/imaging/tiff/tifftags/samplesperpixel.html>`_ = 2
+      for horizontal shift grid, with the first sample being the longitude offset
+      and the second sample being the latitude offset.
+
+    * SamplesPerPixel = 1 for vertical shift grids.
+
+   In the future, different values of SamplesPerPixel may be used to accomodate
+   for other needs. For example for deformation models, SamplesPerPixel = 3 to combine
+   horizontal and vertical adjustments.
+   And even for the current identified needs of horizontal or vertical shifts,
+   more samples may be present (to indicate for example uncertainties), but
+   will be ignored by PROJ.
+
+   The `ExtraSamples <https://www.awaresystems.be/imaging/tiff/tifftags/extrasamples.html>`_
+   tag should be set to a value of SamplesPerPixel - 1 (given the rules that
+   apply for PhotometricInterpretation = MinIsBlack)
+
+- The `ImageDescription <https://www.awaresystems.be/imaging/tiff/tifftags/imagedescription.html>`_
+  tag may be used to convey extra information about the name, provenance, version
+  and last updated date of the grid.
+  Will be set when possible fo files hosted on the CDN.
+  Ignored by PROJ.
+
+- The `Copyright <https://www.awaresystems.be/imaging/tiff/tifftags/copyright.html>`_
+  tag may be used to convey extra information about the copyright and license of the grid.
+  Will be set when possible fo files hosted on the CDN.
+  Ignored by PROJ.
+
+- The `DateTime <https://www.awaresystems.be/imaging/tiff/tifftags/datetime.html>`_
+  tag may be used to convey the date at which the file has been created or
+  converted. In case of a file conversion, for example from NTv2, this will be
+  the date at which the conversion has been performed. The ``ImageDescription``
+  tag however will contain the latest of the CREATED or UPDATED fields from the NTv2 file.
+  Will be set when possible fo files hosted on the CDN.
+  Ignored by PROJ.
+
+- Files hosted on the CDN will use the `GDAL_NODATA
+  <https://www.awaresystems.be/imaging/tiff/tifftags/gdal_nodata.html>`_ tag to encode
+  the value of the nodata / missing value, when it applies to the grid.
+
+  If offset and/or scaling is used, the nodata value corresponds to the raw value,
+  before applying offset and scaling.
+  The value found in this tag, if present, will be honoured (to the extent to
+  which current PROJ code makes use of nodata).
+  For floating point data, writers are strongly discouraged to use non-finite values
+  (+/- infinity, NaN) of nodata to maximimize interoperability.
+  The GDAL_NODATA value applies to all samples of a given TIFF IFD.
+
+- Files hosted on the CDN will use the `GDAL_METADATA
+  <https://www.awaresystems.be/imaging/tiff/tifftags/gdal_metadata.html>`_ tag to encode extra
+  metadata not supported by baseline or extended TIFF.
+
+  * The root XML node should be ``GDALMetadata``
+
+  * Zero, one or several child XML nodes ``Item`` may be present.
+
+  * A Item should have a ``name`` attribute, and a child text node with its value.
+    ``role`` and ``sample`` attributes may be present for attributes that have
+    a special semantics (recognized by GDAL). The value of `sample` should be
+    a integer value between 0 and number_of_samples - 1.
+
+  * Scale and offset to convert integer raw values to floating point values
+    may be expressed with XML `Item` elements whose name attribute is respectively
+    ``SCALE`` and ``OFFSET``, and their ``role`` attribute is respectively ``scale``
+    and ``offset``. The decoded value will be: {offset} + {scale} * raw_value_from_geotiff_file
+
+    For a offset value of 1 and scaling of 2, the following payload should be
+    stored:
+
+    .. code-block:: xml
+
+        <GDALMetadata>
+            <Item name="OFFSET" sample="0" role="offset">1</Item>
+            <Item name="SCALE" sample="0" role="scale">2</Item>
+        </GDALMetadata>
+
+  * The type of the grid must be specified with a `Item` whose ``name`` is set
+    to ``TYPE``.
+
+    Values recognized by PROJ currently are:
+
+    - ``HORIZONTAL_OFFSET``: implies the presence of at least two samples.
+      The first sample must contain the latitude offset and the second
+      sample must contain the longitude offset.
+      Corresponds to PROJ ``hgridshift`` method.
+
+    - ``VERTICAL_OFFSET_GEOGRAPHIC_TO_VERTICAL``: implies the presence of at least one sample.
+      The first sample must contain the vertical adjustment. Must be used when
+      the source/interpolation CRS is a Geographic CRS and the target CRS a Vertical CRS.
+      Corresponds to PROJ ``vgridshift`` method.
+
+    - ``VERTICAL_OFFSET_VERTICAL_TO_VERTICAL``: implies the presence of at least one sample.
+      The first sample must contain the vertical adjustment. Must be used when
+      the source and target CRS are Vertical CRS.
+      Corresponds to PROJ ``vgridshift`` method.
+
+    - ``GEOCENTRIC_TRANSLATION``: implies the presence of at least 3 samples.
+      The first 3 samples must be respectively the geocentric adjustments along
+      the X, Y and Z axis. Must be used when the source and target CRS are
+      geocentric CRS. The interpolation CRS must be a geographic CRS.
+      Corresponds to PROJ ``xyzgridshift`` method.
+
+    - ``VELOCITY``: implies the presence of at least 3 samples.
+      The first 3 samples must be respectively the velocities along
+      the E(ast), N(orth), U(p) axis in the local topocentric coordinate system.
+      Corresponds to PROJ ``deformation`` method.
+
+    For example:
+
+    .. code-block:: xml
+
+        <Item name="TYPE">HORIZONTAL_OFFSET</Item>
+
+  * The description of each sample must be specified with a Item whose ``name``
+    attribute is set to ``DESCRIPTION`` and ``role`` attribute to ``description``.
+
+    Values recognized by PROJ for this Item are currently:
+
+    + ``latitude_offset``: valid for TYPE=HORIZONTAL_OFFSET. Sample values should be
+      the value to add a latitude expressed in the CRS encoded in the GeoKeys
+      to obtain a latitude value expressed in the target CRS.
+
+    + ``longitude_offset``: valid for TYPE=HORIZONTAL_OFFSET. Sample values should be
+      the value to add a longitude expressed in the CRS encoded in the GeoKeys
+      to obtain a longitude value expressed in the target CRS.
+
+    + ``geoid_undulation``: valid for TYPE=VERTICAL_OFFSET_GEOGRAPHIC_TO_VERTICAL.
+      For a source CRS being a geographic CRS and a target CRS being a vertical CRS,
+      sample values should be the value to add to a geoid-related height (that
+      is expressed in the target CRS) to
+      get an ellipsoidal height (that is expressed in the source CRS), also
+      called the geoid undulation.
+      Note the possible confusion related to what is the source CRS and target CRS and
+      the semantics of the value stored (to convert from the source to the target,
+      one must subtract the value contained in the grid). This is the convention
+      used by the `EPSG:9665 <https://www.epsg-registry.org/export.htm?gml=urn:ogc:def:method:EPSG::9665>`_
+      operation method.
+
+    + ``vertical_offset``: valid for TYPE=VERTICAL_OFFSET_VERTICAL_TO_VERTICAL.
+      For a source and target CRS being vertical CRS,
+      sample values should be the value to add to an elevation expressed in the
+      source CRS to obtain a longitude value expressed in the target CRS.
+
+    + ``x_translation`` / ``y_translation`` / ``z_translation``: valid for
+      TYPE=GEOCENTRIC_TRANSLATION.
+      Sample values should be the value to add to the input geocentric coordinates
+      expressed in the source CRS to geocentric coordinates expressed in the target CRS.
+
+    + ``east_velocity`` / ``north_velocity`` / ``up_velocity``: valid for
+      TYPE=VELOCITY.
+      Sample values should be the velocity in a linear/time unit in a ENU local
+      topocentric coordinate system.
+
+    For example:
+
+    .. code-block:: xml
+
+        <Item name="DESCRIPTION" sample="0" role="description">latitude_offset</Item>
+        <Item name="DESCRIPTION" sample="1" role="description">longitude_offset</Item>
+
+    Other values may be used (not used by PROJ):
+
+    + ``latitude_offset_accuracy``: valid for TYPE=HORIZONTAL_OFFSET. Sample values should be
+      the accuracy of corresponding latitude_offset samples. Generally in metre (if converted from NTv2)
+
+    + ``longitude_offset_accuracy``: valid for TYPE=HORIZONTAL_OFFSET. Sample values should be
+      the accuracy of corresponding longitude_offset samples. Generally in metre (if converted from NTv2)
+
+  * The sign convention for the values of the ``longitude_offset`` channel
+    should be indicated with an Item named ``positive_value`` whose value
+    can be ``west`` or ``east``. NTv2 products originally use a ``west``
+    convention, but when converting from them to GeoTIFF, the sign of those
+    samples will be inverted so they use a more natural ``east`` convention.
+    If this item is absent, the default value is ``east``.
+
+  * The unit of the values stored in the grid must be specified for each
+    sample through an Item of name ``UNITTYPE`` and role ``unittype``
+    Valid values should be the name of entries from the EPSG ``unitofmeasure``
+    table. To maximize interoperability, writers are strongly encouraged to
+    limit themselves to the following values:
+
+    For linear units:
+
+    - ``metre`` (default value assumed if absent for vertical shift grid files, and value used for files stored on PROJ CDN)
+    - ``US survey foot``
+
+    For angular units:
+
+    - ``degree``
+    - ``arc-second`` (default value assumed if absent for longitude and latitude offset samples of horizontal shift grid files, and value used for files stored on PROJ CDN)
+
+    For velocity units:
+
+    - ``millimetres per year``
+
+    The longitude and latitude offset samples should use the same unit.
+    The geocentric translation samples should use the same unit.
+    The velocity samples should use the same unit.
+
+    Example:
+
+    .. code-block:: xml
+
+        <Item name="UNITTYPE" sample="0" role="unittype">arc-second</Item>
+        <Item name="UNITTYPE" sample="1" role="unittype">arc-second</Item>
+
+  * The ``target_crs_epsg_code`` metadata item should be present.
+    For a horizontal shift grid, this is the EPSG
+    code of the target geographic CRS. For a vertical shift grid, this is the
+    EPSG code of a the target vertical CRS.
+    If the target CRS has no associated EPSG code, ``target_crs_wkt`` must be
+    used.
+    Ignored by PROJ currently.
+
+  * The ``target_crs_wkt`` metadata item must be present if the
+    ``target_crs_epsg_code`` cannot be used.
+    Its value should be a valid WKT string according to
+    `WKT:2015 <http://docs.opengeospatial.org/is/12-063r5/12-063r5.html>`_
+    or `WKT:2019 <hhttp://docs.opengeospatial.org/is/18-010r7/18-010r7.html>`_
+    Ignored by PROJ currently.
+
+  * The ``source_crs_epsg_code`` metadata item must be present if the source
+    and interpolation CRS are not the same (typical use case is vertical CRS to vertical CRS
+    transformation), because the GeoKeys encode the interpolation CRS and not the source CRS.
+    If the source CRS has no associated EPSG code, ``source_crs_wkt`` must be
+    used.
+    Ignored by PROJ currently.
+
+  * The ``source_crs_wkt`` metadata item must be present if the
+    ``source_crs_epsg_code`` cannot be used.
+    Its value should be a valid WKT string according to WKT:2015 or WKT:2019.
+    Ignored by PROJ currently.
+
+  * The ``interpolation_crs_wkt`` metadata item may be present if the GeoKeys
+    cannot be used to express reliably the interpolation CRS.
+    Its value should be a valid WKT string according to WKT:2015 or WKT:2019.
+    Ignored by PROJ currently.
+
+  * The ``recommended_interpolation_method`` metadata item may be present to
+    describe the method to use to interpolation values at locations not
+    coincident with nodes stored in the grid file. Potential values: ``bilinear``,
+    ``bicubic``.
+    Ignored by PROJ currently.
+
+  * The ``area_of_use`` metadata item can be used to indicate plain text information
+    about the area of use of the grid (like "USA - Wisconsin"). In case of multiple
+    subgrids, it should be set only on the first one, but applies to the whole
+    set of grids, not just the first one.
+
+  * The ``grid_name`` metadata item should be present if there are
+    subgrids for this grid (that is grids whose extent is contained in the extent
+    of this grid), or if this is a subgrid.
+    It is intended to be a relatively short identifier
+    Will be ignored by PROJ (this information can be inferred by the grids extent)
+
+  * The ``parent_grid_name`` metadata item should be present if this is a
+    subgrid and its value should be equal to the paren's ``grid_name``
+    Will be ignored by PROJ (this information can be inferred by the grids extent)
+
+  * The ``number_of_nested_grids`` metadata item should be present if there are
+    subgrids for this grid (that is grids whose extent is contained in the extent
+    of this grid).
+    Will be ignored by PROJ (this information can be inferred by the grids extent)
+
+Example
++++++++
+
+https://github.com/rouault/sample_proj_gtiff_grids/blob/master/ntf_r93.tif has
+been converted from https://github.com/OSGeo/proj-datumgrid/blob/master/ntf_r93.gsb
+with https://github.com/rouault/sample_proj_gtiff_grids/blob/master/ntv2_to_gtiff.py
+
+::
+
+    $ tiffinfo ntf_r93.tif 
+
+    TIFF Directory at offset 0x4e (78)
+    Image Width: 156 Image Length: 111
+    Bits/Sample: 32
+    Sample Format: IEEE floating point
+    Compression Scheme: AdobeDeflate
+    Photometric Interpretation: min-is-black
+    Extra Samples: 3<unspecified, unspecified, unspecified>
+    Samples/Pixel: 4
+    Rows/Strip: 111
+    Planar Configuration: separate image planes
+    ImageDescription: NTF (EPSG:4275) to RGF93 (EPSG:4171). Converted from ntf_r93.gsb (version IGN07_01, last updated on 2007-10-31)
+    DateTime: 2019:12:09 00:00:00
+    Copyright: Derived from work by IGN France. Open License https://www.etalab.gouv.fr/wp-content/uploads/2014/05/Open_Licence.pdf
+    Tag 33550: 0.100000,0.100000,0.000000
+    Tag 33922: 0.000000,0.000000,0.000000,-5.500000,52.000000,0.000000
+    Tag 34735: 1,1,1,3,1024,0,1,2,1025,0,1,2,2048,0,1,4275
+    Tag 42112: <GDALMetadata>
+    <Item name="grid_name">FRANCE</Item>
+    <Item name="target_crs_epsg_code">4171</Item>
+    <Item name="TYPE">HORIZONTAL_OFFSET</Item>
+    <Item name="UNITTYPE" sample="0" role="unittype">arc-second</Item>
+    <Item name="DESCRIPTION" sample="0" role="description">latitude_offset</Item>
+    <Item name="positive_value" sample="1">east</Item>
+    <Item name="UNITTYPE" sample="1" role="unittype">arc-second</Item>
+    <Item name="DESCRIPTION" sample="1" role="description">longitude_offset</Item>
+    <Item name="UNITTYPE" sample="2" role="unittype">arc-second</Item>
+    <Item name="DESCRIPTION" sample="2" role="description">latitude_offset_accuracy</Item>
+    <Item name="UNITTYPE" sample="3" role="unittype">arc-second</Item>
+    <Item name="DESCRIPTION" sample="3" role="description">longitude_offset_accuracy</Item>
+    </GDALMetadata>
+
+    Predictor: floating point predictor 3 (0x3)
+
+
+::
+
+    $ listgeo ntf_r93.tif 
+
+    Geotiff_Information:
+        Version: 1
+        Key_Revision: 1.1
+        Tagged_Information:
+            ModelTiepointTag (2,3):
+                0                 0                 0                
+                -5.5              52                0                
+            ModelPixelScaleTag (1,3):
+                0.1               0.1               0                
+            End_Of_Tags.
+        Keyed_Information:
+            GTModelTypeGeoKey (Short,1): ModelTypeGeographic
+            GTRasterTypeGeoKey (Short,1): RasterPixelIsPoint
+            GeodeticCRSGeoKey (Short,1): Code-4275 (NTF)
+            End_Of_Keys.
+        End_Of_Geotiff.
+
+    GCS: 4275/NTF
+    Datum: 6275/Nouvelle Triangulation Francaise
+    Ellipsoid: 7011/Clarke 1880 (IGN) (6378249.20,6356515.00)
+    Prime Meridian: 8901/Greenwich (0.000000/  0d 0' 0.00"E)
+    Projection Linear Units: User-Defined (1.000000m)
+
+    Corner Coordinates:
+    Upper Left    (  5d30' 0.00"W, 52d 0' 0.00"N)
+    Lower Left    (  5d30' 0.00"W, 40d54' 0.00"N)
+    Upper Right   ( 10d 6' 0.00"E, 52d 0' 0.00"N)
+    Lower Right   ( 10d 6' 0.00"E, 40d54' 0.00"N)
+    Center        (  2d18' 0.00"E, 46d27' 0.00"N)
+
+::
+
+    $ gdalinfo ntf_r93.tif
+
+    Driver: GTiff/GeoTIFF
+    Files: ntf_r93.tif
+    Size is 156, 111
+    Coordinate System is:
+    GEOGCRS["NTF",
+        DATUM["Nouvelle Triangulation Francaise",
+            ELLIPSOID["Clarke 1880 (IGN)",6378249.2,293.466021293627,
+                LENGTHUNIT["metre",1]]],
+        PRIMEM["Greenwich",0,
+            ANGLEUNIT["degree",0.0174532925199433]],
+        CS[ellipsoidal,2],
+            AXIS["geodetic latitude (Lat)",north,
+                ORDER[1],
+                ANGLEUNIT["degree",0.0174532925199433]],
+            AXIS["geodetic longitude (Lon)",east,
+                ORDER[2],
+                ANGLEUNIT["degree",0.0174532925199433]],
+        ID["EPSG",4275]]
+    Data axis to CRS axis mapping: 2,1
+    Origin = (-5.550000000000000,52.049999999999997)
+    Pixel Size = (0.100000000000000,-0.100000000000000)
+    Metadata:
+      AREA_OR_POINT=Point
+      grid_name=FRANCE
+      target_crs_epsg_code=4171
+      TIFFTAG_DATETIME=2019:12:09 00:00:00
+      TIFFTAG_IMAGEDESCRIPTION=NTF (EPSG:4275) to RGF93 (EPSG:4171). Converted from ntf_r93.gsb (version IGN07_01, last updated on 2007-10-31)
+      TYPE=HORIZONTAL_OFFSET
+    Image Structure Metadata:
+      COMPRESSION=DEFLATE
+      INTERLEAVE=BAND
+    Corner Coordinates:
+    Upper Left  (  -5.5500000,  52.0500000) (  5d33' 0.00"W, 52d 3' 0.00"N)
+    Lower Left  (  -5.5500000,  40.9500000) (  5d33' 0.00"W, 40d57' 0.00"N)
+    Upper Right (  10.0500000,  52.0500000) ( 10d 3' 0.00"E, 52d 3' 0.00"N)
+    Lower Right (  10.0500000,  40.9500000) ( 10d 3' 0.00"E, 40d57' 0.00"N)
+    Center      (   2.2500000,  46.5000000) (  2d15' 0.00"E, 46d30' 0.00"N)
+    Band 1 Block=156x111 Type=Float32, ColorInterp=Gray
+      Description = latitude_offset
+      Unit Type: arc-second
+    Band 2 Block=156x111 Type=Float32, ColorInterp=Undefined
+      Description = longitude_offset
+      Unit Type: arc-second
+      Metadata:
+        positive_value=east
+    Band 3 Block=156x111 Type=Float32, ColorInterp=Undefined
+      Description = latitude_offset_accuracy
+      Unit Type: arc-second
+    Band 4 Block=156x111 Type=Float32, ColorInterp=Undefined
+      Description = longitude_offset_accuracy
+      Unit Type: arc-second
+
+Multi-grid storage
+++++++++++++++++++
+
+Formats like NTv2 can contain multiple subgrids. This can be transposed to
+TIFF by using several IFD chained together with the last 4 bytes (or 8 bytes
+for BigTIFF) of an IFD pointing to the offset of the next one.
+
+The first IFD should have a full description according to the
+:ref:`General description <gtg_general_description>`.
+Subsequent IFD might have a more compact description, omitting for example, CRS
+information if it is identical to the main IFD (which should be the case for
+the currently envisionned use cases), or Copyright / ImageDescription metadata
+items.
+
+Each IFD will have its
+`NewSubfileType <https://www.awaresystems.be/imaging/tiff/tifftags/newsubfiletype.html>`_
+tag set to 0.
+
+If a low-resolution grid is available, it should be put before subgrids of
+higher-resolution in the chain of IFD linking. On reading, PROJ will use the
+value from the highest-resoluted grid that contains the point of interest.
+
+For efficient reading from the network, files hosted on the CDN will use
+a layout similar to the one described in the `low level paragraph of the Cloud Optimized GeoTIFF
+GDAL driver page <https://gdal.org/drivers/raster/cog.html#low-level>`_
+
+The layout for a file converted from NTv2 will for example be:
+
+- TIFF/BigTIFF header/signature and pointer to first IFD (Image File Directory)
+- "ghost area" indicating the generated process
+- IFD of the first grid, followed by TIFF tags values, excluding the TileOffsets and TileByteCounts arrays
+- ...
+- IFD of the last grid, followed by TIFF tags values, excluding the GDAL_METADATA tag, TileOffsets and TileByteCounts arrays
+- TileOffsets and TileByteCounts arrays for first IFD
+- ...
+- TileOffsets and TileByteCounts arrays for last IFD
+- Value of GDAL_METADATA tag for IFDs following the first IFD
+- First IFD: Data corresponding to latitude offset of Block_0_0
+- First IFD: Data corresponding to longitude offset of Block_0_0
+- First IFD: Data corresponding to latitude offset of Block_0_1
+- First IFD: Data corresponding to longitude offset of Block_0_1
+- ...
+- First IFD: Data corresponding to latitude offset of Block_n_m
+- First IFD: Data corresponding to longitude offset of Block_n_m
+- ...
+- Last IFD: Data corresponding to latitude offset of Block_0_0
+- Last IFD: Data corresponding to longitude offset of Block_0_0
+- Last IFD: Data corresponding to latitude offset of Block_0_1
+- Last IFD: Data corresponding to longitude offset of Block_0_1
+- ...
+- Last IFD: Data corresponding to latitude offset of Block_n_m
+- Last IFD: Data corresponding to longitude offset of Block_n_m
+
+If longitude_offset_accuracy and latitude_offset_accuracy are present, this
+will be followed by:
+
+- First IFD: Data corresponding to latitude offset accuracy of Block_0_0
+- First IFD: Data corresponding to longitude offset accuracy of Block_0_0
+- ...
+- First IFD: Data corresponding to latitude offset accuracy of Block_n_m
+- First IFD: Data corresponding to longitude offset accuracy of Block_n_m
+- ...
+- Last IFD: Data corresponding to latitude offset accuracy of Block_0_0
+- Last IFD: Data corresponding to longitude offset accuracy of Block_0_0
+- ...
+- Last IFD: Data corresponding to latitude offset accuracy of Block_n_m
+- Last IFD: Data corresponding to longitude offset accuracy of Block_n_m
+
+.. note::
+
+    TIFF has another mechanism to link IFDs, the SubIFD tag. This potentially
+    enables to define a hiearchy of IFDs (similar to HDF5 groups). There is no
+    support for that in most TIFF-using software, notably GDAL, and no compelling
+    need to have a nested hiearchy, so "flat" organization with the standard IFD chaining
+    mechanism is adopted.
+
+Examples of multi-grid dataset
+++++++++++++++++++++++++++++++
+
+https://github.com/rouault/sample_proj_gtiff_grids/blob/master/GDA94_GDA2020_conformal.tif has
+been converted from https://github.com/OSGeo/proj-datumgrid/blob/master/oceania/GDA94_GDA2020_conformal.gsb
+with https://github.com/rouault/sample_proj_gtiff_grids/blob/master/ntv2_to_gtiff.py
+
+It contains 5 subgrids. All essential metadata to list the subgrids and their
+georeferencing is contained within the first 3 KB of the file.
+
+The file size is 4.8 MB using DEFLATE compression and floating-point predictor.
+To be compared with the 83 MB of the original .gsb file.
+
+https://github.com/rouault/sample_proj_gtiff_grids/blob/master/ntv2_0.tif  has
+been converted from https://github.com/OSGeo/proj-datumgrid/blob/master/north-america/ntv2_0.gsb
+
+It contains 114 subgrids. All essential metadata to list the subgrids and their
+georeferencing is contained within the first 40 KB of the file.

docs/source/specifications/index.rst

@@ -0,0 +1,14 @@
+.. _specifications:
+
+================================================================================
+Specifications
+================================================================================
+
+PROJ implements a number of extensions to standards, that are described below
+for the sake of broader interoperability.
+
+.. toctree::
+   :maxdepth: 1
+
+   projjson
+   geodetictiffgrids

docs/source/usage/differences.rst

@@ -139,3 +139,9 @@ cs2cs
 
 Removed ``-ld`` option from application, since it promoted use of deprecated
 paramters like ``+towgs`` and ``+datum``.
+
+UTF-8 adoption
+--------------
+
+The value of all path, filenames passed to PROJ through function calls, PROJ
+strings or environment variables should be encoded in UTF-8.

docs/source/usage/environmentvars.rst

@@ -56,3 +56,21 @@ done by setting the variable with no content::
     Set the debug level of PROJ. The default debug level is zero, which results
     in no debug output when using PROJ. A number from 1-3, whit 3 being the most
     verbose setting.
+
+.. envvar:: PROJ_NETWORK
+
+    .. versionadded:: 7.0.0
+
+    If set to ON, enable the capability to use remote grids stored on CDN
+    (Content Delivery Network) storage, when grids are not available locally.
+    Alternatively, the :c:func:`proj_context_set_enable_network` function can
+    be used.
+
+.. envvar:: PROJ_NETWORK_ENDPOINT
+
+    .. versionadded:: 7.0.0
+
+    Define the endpoint of the CDN storage. Normally defined through the proj.ini
+    configuration file locale in :envvar:`PROJ_LIB`.
+    Alternatively, the :c:func:`proj_context_set_url_endpoint` function can
+    be used.

docs/source/usage/index.rst

@@ -17,5 +17,4 @@ command line applications or the C API that is a part of the software package.
    transformation
    environmentvars
    differences
-   projjson
-
+   network

docs/source/usage/network.rst

@@ -0,0 +1,102 @@
+.. _network:
+
+================================================================================
+Network capabilities
+================================================================================
+
+.. versionadded:: 7.0
+
+PROJ 7.0 has introduced, per :ref:`rfc4`, the capability to work with grid files
+that are not installed on the local machine where PROJ is executed.
+
+This enables to transparently download the parts of grids that are needed to
+perform a coordinate transformation.
+
+.. _cdn_grids:
+
+CDN of GeoTIFF grids
+--------------------
+
+Files are accessed by default through a CDN (Content Delivery Network),
+accessible through https://cdn.proj.org, that contains :ref:`geodetictiffgrids`
+datasets which are mirrored and managed by the
+https://github.com/OSGeo/proj-datumgrid-geotiff/ GitHub project.
+Files in the CDN are designed to be used by PROJ 7 or later, but any software
+project wishing to use the CDN for shifting support are encouraged to
+participate in the project and leverage the CDN. 
+
+How to enable network capabilities ?
+------------------------------------
+
+This capability assumes that PROJ has been build against `libcurl`, and that
+the user authorizes network access.
+
+Authorizing network access can be done in multiple ways:
+
+  - enabling / uncommenting the ``network = on`` line of :ref:`proj-ini`
+  - definiting the :envvar:`PROJ_NETWORK` environment variable to ON
+  - or using the :cpp:func:`proj_context_set_enable_network` with a
+    ``enabled`` = TRUE value.
+
+.. note::
+
+    Instead of using the `libcurl` implementation, an application using the PROJ
+    API can supply its own network implementation through C function callbacks
+    with :cpp:func:`proj_context_set_network_callbacks`. Enabling network use
+    must still be done with one of the above mentionned method.
+
+Setting endpoint
+----------------
+
+When this is enabled, and a grid is not found in the various locations where
+:ref:`resource files are looked for <resource_file_paths>`, PROJ will then
+attempt at loading the file from a remote server, which defaults to
+https://cdn.proj.org in :ref:`proj-ini`. This location can be changed with
+the :envvar:`PROJ_NETWORK_ENDPOINT` environment variable or with
+:cpp:func:`proj_context_set_url_endpoint`.
+
+Caching
+-------
+
+To avoid repeated access to network, a local cache of downloaded chunks of grids
+is implemented as SQLite3 database, ``cache.db``, stored in the
+:ref:`PROJ user writable directory <user_writable_directory>`.
+
+This local caching is enabled by default (can be changed in :ref:`proj-ini` or
+with :cpp:func:`proj_grid_cache_set_enable`). The default maximum size of the
+cache is 300 MB, which is more than half of the total size of grids available,
+at time of writing. This size can also be customized in :ref:`proj-ini` or
+with :cpp:func:`proj_grid_cache_set_max_size`
+
+Download API
+------------
+
+When on-demand loading of grid is not desirable, the PROJ API also offers the
+capability to download whole grids in the
+:ref:`PROJ user writable directory <user_writable_directory>` by using the
+:cpp:func:`proj_is_download_needed` and :cpp:func:`proj_download_file` functions.
+
+
+Mirroring
+---------
+
+If you are able, you are encouraged to mirror the grids via AWS S3 command line:
+
+::
+
+    aws s3 sync s3://cdn.proj.org .
+
+If direct S3 access is not possible, you can also use wget to locally mirror the
+data:
+
+::
+
+    wget --mirror https://cdn.proj.org/
+
+Acknowledgments
+---------------
+
+The s3://cdn.proj.org bucket is hosted by the
+`Amazon Public Datasets program <https://aws.amazon.com/opendata/public-datasets/>`_.
+CDN services are provided by the AWS Public Dataset team via
+`CloudFront <https://aws.amazon.com/cloudfront/>`_

include/proj/coordinateoperation.hpp

@@ -144,10 +144,12 @@ class PROJ_GCC_DLL CoordinateOperation : public common::ObjectUsage,
 
     /** \brief Return grids needed by an operation. */
     PROJ_DLL virtual std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const = 0;
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const = 0;
 
     PROJ_DLL bool
-    isPROJInstantiable(const io::DatabaseContextPtr &databaseContext) const;
+    isPROJInstantiable(const io::DatabaseContextPtr &databaseContext,
+                       bool considerKnownGridsAsAvailable) const;
 
     PROJ_DLL bool hasBallparkTransformation() const;
 
@@ -601,7 +603,8 @@ class PROJ_GCC_DLL SingleOperation : virtual public CoordinateOperation {
             std::vector<metadata::PositionalAccuracyNNPtr>());
 
     PROJ_DLL std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override;
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override;
 
     PROJ_DLL std::list<std::string> validateParameters() const;
 
@@ -1680,7 +1683,8 @@ class PROJ_GCC_DLL ConcatenatedOperation final : public CoordinateOperation {
         bool checkExtent); // throw InvalidOperation
 
     PROJ_DLL std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override;
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override;
 
     PROJ_PRIVATE :
 
@@ -1810,6 +1814,12 @@ class PROJ_GCC_DLL CoordinateOperationContext {
         /** Ignore grid availability at all. Results will be presented as if
          * all grids were available. */
         IGNORE_GRID_AVAILABILITY,
+
+        /** Results will be presented as if grids known to PROJ (that is
+        * registered in the grid_alternatives table of its database) were
+        * available. Used typically when networking is enabled.
+        */
+        KNOWN_AVAILABLE,
     };
 
     PROJ_DLL void setGridAvailabilityUse(GridAvailabilityUse use);

include/proj/internal/coordinateoperation_internal.hpp

@@ -180,8 +180,10 @@ class InverseConversion : public Conversion, public InverseCoordinateOperation {
     // 'osgeo::proj::operation::SingleOperation::osgeo::proj::operation::SingleOperation::gridsNeeded'
     // via dominance
     std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override {
-        return SingleOperation::gridsNeeded(databaseContext);
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override {
+        return SingleOperation::gridsNeeded(databaseContext,
+                                            considerKnownGridsAsAvailable);
     }
 #endif
 
@@ -232,8 +234,10 @@ class InverseTransformation : public Transformation,
     // 'osgeo::proj::operation::SingleOperation::osgeo::proj::operation::SingleOperation::gridsNeeded'
     // via dominance
     std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override {
-        return SingleOperation::gridsNeeded(databaseContext);
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override {
+        return SingleOperation::gridsNeeded(databaseContext,
+                                            considerKnownGridsAsAvailable);
     }
 #endif
 
@@ -274,7 +278,8 @@ class PROJBasedOperation : public SingleOperation {
            bool hasRoughTransformation);
 
     std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override;
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override;
 
   protected:
     PROJBasedOperation(const PROJBasedOperation &) = default;

include/proj/io.hpp

@@ -832,6 +832,7 @@ class PROJ_GCC_DLL DatabaseContext {
                                               bool &inverse) const;
 
     PROJ_DLL bool lookForGridInfo(const std::string &projFilename,
+                                  bool considerKnownGridsAsAvailable,
                                   std::string &fullFilename,
                                   std::string &packageName, std::string &url,
                                   bool &directDownload, bool &openLicense,
@@ -1055,7 +1056,8 @@ class PROJ_GCC_DLL AuthorityFactory {
         const std::string &sourceCRSAuthName, const std::string &sourceCRSCode,
         const std::string &targetCRSAuthName, const std::string &targetCRSCode,
         bool usePROJAlternativeGridNames, bool discardIfMissingGrid,
-        bool discardSuperseded, bool tryReverseOrder = false,
+        bool considerKnownGridsAsAvailable, bool discardSuperseded,
+        bool tryReverseOrder = false,
         bool reportOnlyIntersectingTransformations = false,
         const metadata::ExtentPtr &intersectingExtent1 = nullptr,
         const metadata::ExtentPtr &intersectingExtent2 = nullptr) const;
@@ -1065,7 +1067,7 @@ class PROJ_GCC_DLL AuthorityFactory {
         const std::string &sourceCRSAuthName, const std::string &sourceCRSCode,
         const std::string &targetCRSAuthName, const std::string &targetCRSCode,
         bool usePROJAlternativeGridNames, bool discardIfMissingGrid,
-        bool discardSuperseded,
+        bool considerKnownGridsAsAvailable, bool discardSuperseded,
         const std::vector<std::pair<std::string, std::string>>
             &intermediateCRSAuthCodes,
         ObjectType allowedIntermediateObjectType = ObjectType::CRS,
@@ -1131,7 +1133,7 @@ class PROJ_GCC_DLL AuthorityFactory {
         const std::string &sourceCRSCode, const crs::CRSNNPtr &targetCRS,
         const std::string &targetCRSAuthName, const std::string &targetCRSCode,
         bool usePROJAlternativeGridNames, bool discardIfMissingGrid,
-        bool discardSuperseded,
+        bool considerKnownGridsAsAvailable, bool discardSuperseded,
         const std::vector<std::string> &allowedAuthorities,
         const metadata::ExtentPtr &intersectingExtent1,
         const metadata::ExtentPtr &intersectingExtent2) const;

scripts/doxygen.sh

@@ -34,7 +34,11 @@ fi
 mkdir -p docs/build/tmp_breathe
 python scripts/generate_breathe_friendly_general_doc.py
 rm -rf docs/build/xml/
-(cat Doxyfile; printf "GENERATE_HTML=NO\nGENERATE_XML=YES\nINPUT= src/iso19111 include/proj src/proj.h docs/build/tmp_breathe/general_doc.dox.reworked.h") | doxygen -  > docs/build/tmp_breathe/docs_log.txt 2>&1
+
+# Ugly hack to workaround a bug of Doxygen 1.8.17 that erroneously detect proj_network_get_header_value_cbk_type/ as a variable
+sed "s/const char\* (\*proj_network_get_header_value_cbk_type/CONST_CHAR\* (\*proj_network_get_header_value_cbk_type/" < src/proj.h > docs/build/tmp_breathe/proj.h
+
+(cat Doxyfile; printf "GENERATE_HTML=NO\nGENERATE_XML=YES\nINPUT= src/iso19111 include/proj docs/build/tmp_breathe/proj.h src/filemanager.cpp src/networkfilemanager.cpp docs/build/tmp_breathe/general_doc.dox.reworked.h") | doxygen -  > docs/build/tmp_breathe/docs_log.txt 2>&1
 if grep -i warning docs/build/tmp_breathe/docs_log.txt; then
     echo "Doxygen warnings found" && cat docs/build/tmp_breathe/docs_log.txt && /bin/false;
 else
@@ -56,5 +60,9 @@ done
 sed "s/Convention/Convention_/g" < ${TOPDIR}/docs/build/xml/classosgeo_1_1proj_1_1io_1_1WKTFormatter.xml | sed "s/WKT2_2018/_WKT2_2018/g" | sed "s/WKT2_2019/_WKT2_2019/g" | sed "s/WKT2_2015/_WKT2_2015/g" | sed "s/WKT1_GDAL/_WKT1_GDAL/g" | sed "s/WKT1_ESRI/_WKT1_ESRI/g" > ${TOPDIR}/docs/build/xml/classosgeo_1_1proj_1_1io_1_1WKTFormatter.xml.tmp
 mv ${TOPDIR}/docs/build/xml/classosgeo_1_1proj_1_1io_1_1WKTFormatter.xml.tmp  ${TOPDIR}/docs/build/xml/classosgeo_1_1proj_1_1io_1_1WKTFormatter.xml
 
+# Ugly hack to workaround a bug of Doxygen 1.8.17 that erroneously detect proj_network_get_header_value_cbk_type/ as a variable
+sed "s/CONST_CHAR/const char/"  < ${TOPDIR}/docs/build/xml/proj_8h.xml > ${TOPDIR}/docs/build/xml/proj_8h.xml.tmp
+mv ${TOPDIR}/docs/build/xml/proj_8h.xml.tmp ${TOPDIR}/docs/build/xml/proj_8h.xml
+
 popd > /dev/null || exit
 

scripts/reference_exported_symbols.txt

@@ -281,6 +281,26 @@ osgeo::proj::datum::TemporalDatum::temporalOrigin() const
 osgeo::proj::datum::VerticalReferenceFrame::create(osgeo::proj::util::PropertyMap const&, osgeo::proj::util::optional<std::string> const&, osgeo::proj::util::optional<osgeo::proj::datum::RealizationMethod> const&)
 osgeo::proj::datum::VerticalReferenceFrame::realizationMethod() const
 osgeo::proj::datum::VerticalReferenceFrame::~VerticalReferenceFrame()
+osgeo::proj::GenericShiftGrid::~GenericShiftGrid()
+osgeo::proj::GenericShiftGrid::GenericShiftGrid(std::string const&, int, int, osgeo::proj::ExtentAndRes const&)
+osgeo::proj::GenericShiftGrid::gridAt(double, double) const
+osgeo::proj::GenericShiftGridSet::~GenericShiftGridSet()
+osgeo::proj::GenericShiftGridSet::GenericShiftGridSet()
+osgeo::proj::GenericShiftGridSet::gridAt(double, double) const
+osgeo::proj::GenericShiftGridSet::open(projCtx_t*, std::string const&)
+osgeo::proj::GenericShiftGridSet::reassign_context(projCtx_t*)
+osgeo::proj::GenericShiftGridSet::reopen(projCtx_t*)
+osgeo::proj::Grid::~Grid()
+osgeo::proj::Grid::Grid(std::string const&, int, int, osgeo::proj::ExtentAndRes const&)
+osgeo::proj::HorizontalShiftGrid::gridAt(double, double) const
+osgeo::proj::HorizontalShiftGrid::~HorizontalShiftGrid()
+osgeo::proj::HorizontalShiftGrid::HorizontalShiftGrid(std::string const&, int, int, osgeo::proj::ExtentAndRes const&)
+osgeo::proj::HorizontalShiftGridSet::gridAt(double, double) const
+osgeo::proj::HorizontalShiftGridSet::~HorizontalShiftGridSet()
+osgeo::proj::HorizontalShiftGridSet::HorizontalShiftGridSet()
+osgeo::proj::HorizontalShiftGridSet::open(projCtx_t*, std::string const&)
+osgeo::proj::HorizontalShiftGridSet::reassign_context(projCtx_t*)
+osgeo::proj::HorizontalShiftGridSet::reopen(projCtx_t*)
 osgeo::proj::internal::ci_equal(std::string const&, char const*)
 osgeo::proj::internal::ci_equal(std::string const&, std::string const&)
 osgeo::proj::internal::ci_find(std::string const&, char const*)
@@ -301,8 +321,8 @@ osgeo::proj::io::AuthorityFactory::create(dropbox::oxygen::nn<std::shared_ptr<os
 osgeo::proj::io::AuthorityFactory::createEllipsoid(std::string const&) const
 osgeo::proj::io::AuthorityFactory::createExtent(std::string const&) const
 osgeo::proj::io::AuthorityFactory::createFromCoordinateReferenceSystemCodes(std::string const&, std::string const&) const
-osgeo::proj::io::AuthorityFactory::createFromCoordinateReferenceSystemCodes(std::string const&, std::string const&, std::string const&, std::string const&, bool, bool, bool, bool, bool, std::shared_ptr<osgeo::proj::metadata::Extent> const&, std::shared_ptr<osgeo::proj::metadata::Extent> const&) const
-osgeo::proj::io::AuthorityFactory::createFromCRSCodesWithIntermediates(std::string const&, std::string const&, std::string const&, std::string const&, bool, bool, bool, std::vector<std::pair<std::string, std::string>, std::allocator<std::pair<std::string, std::string> > > const&, osgeo::proj::io::AuthorityFactory::ObjectType, std::vector<std::string, std::allocator<std::string> > const&, std::shared_ptr<osgeo::proj::metadata::Extent> const&, std::shared_ptr<osgeo::proj::metadata::Extent> const&) const
+osgeo::proj::io::AuthorityFactory::createFromCoordinateReferenceSystemCodes(std::string const&, std::string const&, std::string const&, std::string const&, bool, bool, bool, bool, bool, bool, std::shared_ptr<osgeo::proj::metadata::Extent> const&, std::shared_ptr<osgeo::proj::metadata::Extent> const&) const
+osgeo::proj::io::AuthorityFactory::createFromCRSCodesWithIntermediates(std::string const&, std::string const&, std::string const&, std::string const&, bool, bool, bool, bool, std::vector<std::pair<std::string, std::string>, std::allocator<std::pair<std::string, std::string> > > const&, osgeo::proj::io::AuthorityFactory::ObjectType, std::vector<std::string, std::allocator<std::string> > const&, std::shared_ptr<osgeo::proj::metadata::Extent> const&, std::shared_ptr<osgeo::proj::metadata::Extent> const&) const
 osgeo::proj::io::AuthorityFactory::createGeodeticCRS(std::string const&) const
 osgeo::proj::io::AuthorityFactory::createGeodeticDatum(std::string const&) const
 osgeo::proj::io::AuthorityFactory::createGeographicCRS(std::string const&) const
@@ -332,7 +352,7 @@ osgeo::proj::io::DatabaseContext::getDatabaseStructure() const
 osgeo::proj::io::DatabaseContext::getMetadata(char const*) const
 osgeo::proj::io::DatabaseContext::getPath() const
 osgeo::proj::io::DatabaseContext::getSqliteHandle() const
-osgeo::proj::io::DatabaseContext::lookForGridInfo(std::string const&, std::string&, std::string&, std::string&, bool&, bool&, bool&) const
+osgeo::proj::io::DatabaseContext::lookForGridInfo(std::string const&, bool, std::string&, std::string&, std::string&, bool&, bool&, bool&) const
 osgeo::proj::io::FactoryException::~FactoryException()
 osgeo::proj::io::FactoryException::FactoryException(char const*)
 osgeo::proj::io::FactoryException::FactoryException(osgeo::proj::io::FactoryException const&)
@@ -467,7 +487,7 @@ osgeo::proj::metadata::VerticalExtent::~VerticalExtent()
 osgeo::proj::operation::ConcatenatedOperation::~ConcatenatedOperation()
 osgeo::proj::operation::ConcatenatedOperation::createComputeMetadata(std::vector<dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::operation::CoordinateOperation> >, std::allocator<dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::operation::CoordinateOperation> > > > const&, bool)
 osgeo::proj::operation::ConcatenatedOperation::create(osgeo::proj::util::PropertyMap const&, std::vector<dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::operation::CoordinateOperation> >, std::allocator<dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::operation::CoordinateOperation> > > > const&, std::vector<dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::metadata::PositionalAccuracy> >, std::allocator<dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::metadata::PositionalAccuracy> > > > const&)
-osgeo::proj::operation::ConcatenatedOperation::gridsNeeded(std::shared_ptr<osgeo::proj::io::DatabaseContext> const&) const
+osgeo::proj::operation::ConcatenatedOperation::gridsNeeded(std::shared_ptr<osgeo::proj::io::DatabaseContext> const&, bool) const
 osgeo::proj::operation::ConcatenatedOperation::inverse() const
 osgeo::proj::operation::ConcatenatedOperation::operations() const
 osgeo::proj::operation::Conversion::~Conversion()
@@ -577,7 +597,7 @@ osgeo::proj::operation::CoordinateOperationFactory::createOperation(dropbox::oxy
 osgeo::proj::operation::CoordinateOperationFactory::createOperations(dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::crs::CRS> > const&, dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::crs::CRS> > const&, dropbox::oxygen::nn<std::unique_ptr<osgeo::proj::operation::CoordinateOperationContext, std::default_delete<osgeo::proj::operation::CoordinateOperationContext> > > const&) const
 osgeo::proj::operation::CoordinateOperation::hasBallparkTransformation() const
 osgeo::proj::operation::CoordinateOperation::interpolationCRS() const
-osgeo::proj::operation::CoordinateOperation::isPROJInstantiable(std::shared_ptr<osgeo::proj::io::DatabaseContext> const&) const
+osgeo::proj::operation::CoordinateOperation::isPROJInstantiable(std::shared_ptr<osgeo::proj::io::DatabaseContext> const&, bool) const
 osgeo::proj::operation::CoordinateOperation::normalizeForVisualization() const
 osgeo::proj::operation::CoordinateOperation::operationVersion() const
 osgeo::proj::operation::CoordinateOperation::shallowClone() const
@@ -623,7 +643,7 @@ osgeo::proj::operation::ParameterValue::value() const
 osgeo::proj::operation::ParameterValue::valueFile() const
 osgeo::proj::operation::PointMotionOperation::~PointMotionOperation()
 osgeo::proj::operation::SingleOperation::createPROJBased(osgeo::proj::util::PropertyMap const&, std::string const&, std::shared_ptr<osgeo::proj::crs::CRS> const&, std::shared_ptr<osgeo::proj::crs::CRS> const&, std::vector<dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::metadata::PositionalAccuracy> >, std::allocator<dropbox::oxygen::nn<std::shared_ptr<osgeo::proj::metadata::PositionalAccuracy> > > > const&)
-osgeo::proj::operation::SingleOperation::gridsNeeded(std::shared_ptr<osgeo::proj::io::DatabaseContext> const&) const
+osgeo::proj::operation::SingleOperation::gridsNeeded(std::shared_ptr<osgeo::proj::io::DatabaseContext> const&, bool) const
 osgeo::proj::operation::SingleOperation::method() const
 osgeo::proj::operation::SingleOperation::parameterValue(int) const
 osgeo::proj::operation::SingleOperation::parameterValueMeasure(int) const
@@ -698,6 +718,15 @@ osgeo::proj::util::PropertyMap::set(std::string const&, std::string const&)
 osgeo::proj::util::PropertyMap::set(std::string const&, std::vector<std::string, std::allocator<std::string> > const&)
 osgeo::proj::util::UnsupportedOperationException::~UnsupportedOperationException()
 osgeo::proj::util::UnsupportedOperationException::UnsupportedOperationException(osgeo::proj::util::UnsupportedOperationException const&)
+osgeo::proj::VerticalShiftGrid::gridAt(double, double) const
+osgeo::proj::VerticalShiftGridSet::gridAt(double, double) const
+osgeo::proj::VerticalShiftGridSet::open(projCtx_t*, std::string const&)
+osgeo::proj::VerticalShiftGridSet::reassign_context(projCtx_t*)
+osgeo::proj::VerticalShiftGridSet::reopen(projCtx_t*)
+osgeo::proj::VerticalShiftGridSet::~VerticalShiftGridSet()
+osgeo::proj::VerticalShiftGridSet::VerticalShiftGridSet()
+osgeo::proj::VerticalShiftGrid::~VerticalShiftGrid()
+osgeo::proj::VerticalShiftGrid::VerticalShiftGrid(std::string const&, int, int, osgeo::proj::ExtentAndRes const&)
 pj_acquire_lock
 pj_add_type_crs_if_needed(std::string const&)
 pj_apply_gridshift
@@ -709,6 +738,9 @@ pj_chomp(char*)
 pj_cleanup_lock
 pj_clear_initcache
 pj_compare_datums
+pj_context_get_grid_cache_filename(projCtx_t*)
+pj_context_get_user_writable_directory(projCtx_t*, bool)
+pj_context_is_network_enabled(projCtx_t*)
 pj_ctx_alloc
 pj_ctx_fclose
 pj_ctx_fgets
@@ -796,9 +828,14 @@ proj_context_get_use_proj4_init_rules
 proj_context_guess_wkt_dialect
 proj_context_set_autoclose_database
 proj_context_set_database_path
+proj_context_set_enable_network
+proj_context_set_fileapi
 proj_context_set_file_finder
+proj_context_set_network_callbacks
 proj_context_set(PJconsts*, projCtx_t*)
 proj_context_set_search_paths
+proj_context_set_sqlite3_vfs_name
+proj_context_set_url_endpoint
 proj_context_use_proj4_init_rules
 proj_convert_conversion_to_other_method
 proj_coord
@@ -928,6 +965,7 @@ proj_cs_get_axis_info
 proj_cs_get_type
 proj_destroy
 proj_dmstor
+proj_download_file
 proj_ellipsoid_get_parameters
 proj_errno
 proj_errno_reset
@@ -953,6 +991,11 @@ proj_get_scope
 proj_get_source_crs
 proj_get_target_crs
 proj_get_type
+proj_grid_cache_clear
+proj_grid_cache_set_enable
+proj_grid_cache_set_filename
+proj_grid_cache_set_max_size
+proj_grid_cache_set_ttl
 proj_grid_get_info_from_database
 proj_grid_info
 proj_identify
@@ -962,6 +1005,7 @@ proj_int_list_destroy
 proj_is_crs
 proj_is_deprecated
 proj_is_derived_crs
+proj_is_download_needed
 proj_is_equivalent_to
 proj_is_equivalent_to_with_ctx
 proj_list_angular_units

scripts/reformat_cpp.sh

@@ -15,7 +15,11 @@ esac
 
 TOPDIR="$SCRIPT_DIR/.."
 
-for i in "$TOPDIR"/include/proj/*.hpp "$TOPDIR"/include/proj/internal/*.hpp "$TOPDIR"/src/iso19111/*.cpp "$TOPDIR"/test/unit/*.cpp "$TOPDIR"/src/apps/projinfo.cpp "$TOPDIR"/src/tracing.cpp; do
+for i in "$TOPDIR"/include/proj/*.hpp "$TOPDIR"/include/proj/internal/*.hpp \
+         "$TOPDIR"/src/iso19111/*.cpp "$TOPDIR"/test/unit/*.cpp "$TOPDIR"/src/apps/projinfo.cpp \
+         "$TOPDIR"/src/tracing.cpp "$TOPDIR"/src/grids.hpp "$TOPDIR"/src/grids.cpp \
+         "$TOPDIR"/src/filemanager.hpp "$TOPDIR"/src/filemanager.cpp \
+         "$TOPDIR"/src/sqlite3_utils.hpp "$TOPDIR"/src/sqlite3_utils.cpp ; do
     if ! echo "$i" | grep -q "lru_cache.hpp"; then
         "$SCRIPT_DIR"/reformat.sh "$i";
     fi

src/4D_api.cpp

@@ -47,6 +47,8 @@
 #include "proj_internal.h"
 #include <math.h>
 #include "geodesic.h"
+#include "grids.hpp"
+#include "filemanager.hpp"
 
 #include "proj/common.hpp"
 #include "proj/coordinateoperation.hpp"
@@ -262,6 +264,9 @@ similarly, but prefers the 2D resp. 3D interfaces if available.
             }
             PJ_COORD res = direction == PJ_FWD ?
                         pj_fwd4d( coord, alt.pj ) : pj_inv4d( coord, alt.pj );
+            if( proj_errno(alt.pj) == PJD_ERR_NETWORK_ERROR ) {
+                return proj_coord_error ();
+            }
             if( res.xyzt.x != HUGE_VAL ) {
                 return res;
             }
@@ -290,7 +295,7 @@ similarly, but prefers the 2D resp. 3D interfaces if available.
             auto coordOperation = dynamic_cast<
             NS_PROJ::operation::CoordinateOperation*>(alt.pj->iso_obj.get());
             if( coordOperation ) {
-                if( coordOperation->gridsNeeded(dbContext).empty() ) {
+                if( coordOperation->gridsNeeded(dbContext, true).empty() ) {
                     if( P->iCurCoordOp != i ) {
                         if (proj_log_level(P->ctx, PJ_LOG_TELL) >= PJ_LOG_DEBUG) {
                             std::string msg("Using coordinate operation ");
@@ -1146,7 +1151,10 @@ PJ  *proj_create_crs_to_crs_from_pj (PJ_CONTEXT *ctx, const PJ *source_crs, cons
     proj_operation_factory_context_set_spatial_criterion(
         ctx, operation_ctx, PROJ_SPATIAL_CRITERION_PARTIAL_INTERSECTION);
     proj_operation_factory_context_set_grid_availability_use(
-        ctx, operation_ctx, PROJ_GRID_AVAILABILITY_DISCARD_OPERATION_IF_MISSING_GRID);
+        ctx, operation_ctx,
+        pj_context_is_network_enabled(ctx) ?
+            PROJ_GRID_AVAILABILITY_KNOWN_AVAILABLE:
+            PROJ_GRID_AVAILABILITY_DISCARD_OPERATION_IF_MISSING_GRID);
 
     auto op_list = proj_create_operations(ctx, source_crs, target_crs, operation_ctx);
 
@@ -1476,10 +1484,20 @@ PJ_INFO proj_info (void) {
     /* build search path string */
     auto ctx = pj_get_default_ctx();
     if (!ctx || ctx->search_paths.empty()) {
-        const char *envPROJ_LIB = getenv("PROJ_LIB");
-        buf = path_append(buf, envPROJ_LIB, &buf_size);
+        // Env var mostly for testing purposes and being independent from
+        // an existing installation
+        const char* ignoreUserWritableDirectory =
+            getenv("PROJ_SKIP_READ_USER_WRITABLE_DIRECTORY");
+        if( ignoreUserWritableDirectory == nullptr ||
+            ignoreUserWritableDirectory[0] == '\0'  ) {
+            buf = path_append(buf,
+                            pj_context_get_user_writable_directory(ctx, false).c_str(),
+                            &buf_size);
+        }
+        const std::string envPROJ_LIB = NS_PROJ::FileManager::getProjLibEnvVar(ctx);
+        buf = path_append(buf, envPROJ_LIB.empty() ? nullptr : envPROJ_LIB.c_str(), &buf_size);
 #ifdef PROJ_LIB
-        if (envPROJ_LIB == nullptr) {
+        if (envPROJ_LIB.empty()) {
             buf = path_append(buf, PROJ_LIB, &buf_size);
         }
 #endif
@@ -1583,43 +1601,65 @@ PJ_GRID_INFO proj_grid_info(const char *gridname) {
 
     /*PJ_CONTEXT *ctx = proj_context_create(); */
     PJ_CONTEXT *ctx = pj_get_default_ctx();
-    PJ_GRIDINFO *gridinfo = pj_gridinfo_init(ctx, gridname);
     memset(&grinfo, 0, sizeof(PJ_GRID_INFO));
 
-    /* in case the grid wasn't found */
-    if (gridinfo->filename == nullptr || gridinfo->ct == nullptr) {
-        pj_gridinfo_free(ctx, gridinfo);
-        strcpy(grinfo.format, "missing");
-        return grinfo;
+    const auto fillGridInfo = [&grinfo, ctx, gridname]
+                        (const NS_PROJ::Grid& grid, const std::string& format)
+    {
+        const auto& extent = grid.extentAndRes();
+
+        /* name of grid */
+        strncpy (grinfo.gridname, gridname, sizeof(grinfo.gridname) - 1);
+
+        /* full path of grid */
+        pj_find_file(ctx, gridname, grinfo.filename, sizeof(grinfo.filename) - 1);
+
+        /* grid format */
+        strncpy (grinfo.format, format.c_str(), sizeof(grinfo.format) - 1);
+
+        /* grid size */
+        grinfo.n_lon = grid.width();
+        grinfo.n_lat = grid.height();
+
+        /* cell size */
+        grinfo.cs_lon = extent.resLon;
+        grinfo.cs_lat = extent.resLat;
+
+        /* bounds of grid */
+        grinfo.lowerleft.lam  = extent.westLon;
+        grinfo.lowerleft.phi  = extent.southLat;
+        grinfo.upperright.lam = extent.eastLon;
+        grinfo.upperright.phi = extent.northLat;
+    };
+
+    {
+        const auto gridSet = NS_PROJ::VerticalShiftGridSet::open(ctx, gridname);
+        if( gridSet )
+        {
+            const auto& grids = gridSet->grids();
+            if( !grids.empty() )
+            {
+                const auto& grid = grids.front();
+                fillGridInfo(*grid, gridSet->format());
+                return grinfo;
+            }
+        }
     }
 
-    /* The string copies below are automatically null-terminated due to */
-    /* the memset above, so strncpy is safe */
-
-    /* name of grid */
-    strncpy (grinfo.gridname, gridname, sizeof(grinfo.gridname) - 1);
-
-    /* full path of grid */
-    pj_find_file(ctx, gridname, grinfo.filename, sizeof(grinfo.filename) - 1);
-
-    /* grid format */
-    strncpy (grinfo.format, gridinfo->format, sizeof(grinfo.format) - 1);
-
-    /* grid size */
-    grinfo.n_lon = gridinfo->ct->lim.lam;
-    grinfo.n_lat = gridinfo->ct->lim.phi;
-
-    /* cell size */
-    grinfo.cs_lon = gridinfo->ct->del.lam;
-    grinfo.cs_lat = gridinfo->ct->del.phi;
-
-    /* bounds of grid */
-    grinfo.lowerleft  = gridinfo->ct->ll;
-    grinfo.upperright.lam = grinfo.lowerleft.lam + grinfo.n_lon*grinfo.cs_lon;
-    grinfo.upperright.phi = grinfo.lowerleft.phi + grinfo.n_lat*grinfo.cs_lat;
-
-    pj_gridinfo_free(ctx, gridinfo);
-
+    {
+        const auto gridSet = NS_PROJ::HorizontalShiftGridSet::open(ctx, gridname);
+        if( gridSet )
+        {
+            const auto& grids = gridSet->grids();
+            if( !grids.empty() )
+            {
+                const auto& grid = grids.front();
+                fillGridInfo(*grid, gridSet->format());
+                return grinfo;
+            }
+        }
+    }
+    strcpy(grinfo.format, "missing");
     return grinfo;
 }
 
@@ -1763,3 +1803,4 @@ PJ_FACTORS proj_factors(PJ *P, PJ_COORD lp) {
 
     return factors;
 }
+

src/Makefile.am

@@ -7,7 +7,7 @@ TESTS = geodtest
 check_PROGRAMS = geodtest
 
 AM_CPPFLAGS =	-DPROJ_LIB=\"$(pkgdatadir)\" \
-		-DMUTEX_@MUTEX_SETTING@ -I$(top_srcdir)/include @SQLITE3_CFLAGS@
+		-DMUTEX_@MUTEX_SETTING@ -I$(top_srcdir)/include @SQLITE3_CFLAGS@ @TIFF_CFLAGS@ @TIFF_ENABLED_FLAGS@ @CURL_CFLAGS@ @CURL_ENABLED_FLAGS@
 AM_CXXFLAGS =    @CXX_WFLAGS@ @FLTO_FLAG@
 
 include_HEADERS = proj.h proj_experimental.h proj_constants.h proj_api.h geodesic.h \
@@ -43,7 +43,7 @@ geodtest_LDADD = libproj.la
 lib_LTLIBRARIES = libproj.la
 
 libproj_la_LDFLAGS = -no-undefined -version-info 18:0:3
-libproj_la_LIBADD = @SQLITE3_LIBS@
+libproj_la_LIBADD = @SQLITE3_LIBS@ @TIFF_LIBS@ @CURL_LIBS@
 
 libproj_la_SOURCES = \
 	pj_list.h proj_internal.h \
@@ -183,23 +183,22 @@ libproj_la_SOURCES = \
 	transformations/horner.cpp \
 	transformations/molodensky.cpp \
 	transformations/vgridshift.cpp \
+	transformations/xyzgridshift.cpp \
 	\
 	aasincos.cpp adjlon.cpp \
 	dmstor.cpp auth.cpp \
 	deriv.cpp ell_set.cpp ellps.cpp errno.cpp \
 	factors.cpp fwd.cpp init.cpp inv.cpp \
 	list.cpp malloc.cpp mlfn.cpp msfn.cpp proj_mdist.cpp \
-	open_lib.cpp param.cpp phi2.cpp pr_list.cpp \
+	param.cpp phi2.cpp pr_list.cpp \
 	qsfn.cpp strerrno.cpp \
 	tsfn.cpp units.cpp ctx.cpp log.cpp zpoly1.cpp rtodms.cpp \
 	release.cpp gauss.cpp \
 	fileapi.cpp \
 	\
-	gc_reader.cpp gridcatalog.cpp \
-	nad_cvt.cpp nad_init.cpp nad_intr.cpp \
-	apply_gridshift.cpp datums.cpp datum_set.cpp transform.cpp \
-	geocent.cpp geocent.h utils.cpp gridinfo.cpp gridlist.cpp \
-	mutex.cpp initcache.cpp apply_vgridshift.cpp geodesic.c \
+	datums.cpp datum_set.cpp transform.cpp \
+	geocent.cpp geocent.h utils.cpp \
+	mutex.cpp initcache.cpp geodesic.c \
 	strtod.cpp \
 	\
 	4D_api.cpp pipeline.cpp \
@@ -213,7 +212,15 @@ libproj_la_SOURCES = \
 	proj_json_streaming_writer.hpp \
 	proj_json_streaming_writer.cpp \
 	\
-	tracing.cpp
+	tracing.cpp \
+	\
+	grids.hpp \
+	grids.cpp \
+	filemanager.hpp \
+	filemanager.cpp \
+	networkfilemanager.cpp \
+	sqlite3_utils.hpp \
+	sqlite3_utils.cpp
 
 
 # The sed hack is to please MSVC

src/apply_gridshift.cpp

@@ -1,366 +0,0 @@
-/******************************************************************************
- * Project:  PROJ.4
- * Purpose:  Apply datum shifts based on grid shift files (normally NAD27 to
- *           NAD83 or the reverse).  This module is responsible for keeping
- *           a list of loaded grids, and calling with each one that is
- *           allowed for a given datum (expressed as the nadgrids= parameter).
- * Author:   Frank Warmerdam, warmerdam@pobox.com
- *
- ******************************************************************************
- * Copyright (c) 2000, Frank Warmerdam <warmerdam@pobox.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *****************************************************************************/
-
-#define PJ_LIB__
-
-#include <math.h>
-#include <stdio.h>
-#include <string.h>
-
-#include "proj.h"
-#include "proj_internal.h"
-
-/************************************************************************/
-/*                         pj_apply_gridshift()                         */
-/*                                                                      */
-/*      This is the externally callable interface - part of the         */
-/*      public API - though it is not used internally any more and I    */
-/*      doubt it is used by any other applications.  But we preserve    */
-/*      it to honour our public api.                                    */
-/************************************************************************/
-
-int pj_apply_gridshift( projCtx ctx, const char *nadgrids, int inverse,
-                        long point_count, int point_offset,
-                        double *x, double *y, double *z )
-
-{
-    PJ_GRIDINFO **gridlist;
-    int           grid_count;
-    int           ret;
-
-    gridlist = pj_gridlist_from_nadgrids( ctx, nadgrids, &grid_count );
-
-    if( gridlist == nullptr || grid_count == 0 )
-    {
-        pj_dalloc( gridlist );
-        return ctx->last_errno;
-    }
-
-    ret = pj_apply_gridshift_3( ctx, gridlist, grid_count, inverse,
-                                point_count, point_offset, x, y, z );
-
-    /*
-    ** Note this frees the array of grid list pointers, but not the grids
-    ** which is as intended.  The grids themselves live on.
-    */
-    pj_dalloc( gridlist );
-
-    return ret;
-}
-
-/************************************************************************/
-/*                        pj_apply_gridshift_2()                        */
-/*                                                                      */
-/*      This implementation uses the gridlist from a coordinate         */
-/*      system definition.  If the gridlist has not yet been            */
-/*      populated in the coordinate system definition we set it up      */
-/*      now.                                                            */
-/************************************************************************/
-
-int pj_apply_gridshift_2( PJ *defn, int inverse,
-                          long point_count, int point_offset,
-                          double *x, double *y, double *z )
-
-{
-    if( defn->catalog_name != nullptr )
-        return pj_gc_apply_gridshift( defn, inverse, point_count, point_offset,
-                                      x, y, z );
-
-    if( defn->gridlist == nullptr )
-    {
-        defn->gridlist =
-            pj_gridlist_from_nadgrids( pj_get_ctx( defn ),
-                                       pj_param(defn->ctx, defn->params,"snadgrids").s,
-                                       &(defn->gridlist_count) );
-
-        if( defn->gridlist == nullptr || defn->gridlist_count == 0 )
-            return defn->ctx->last_errno;
-    }
-
-    return pj_apply_gridshift_3( pj_get_ctx( defn ),
-                                 defn->gridlist, defn->gridlist_count, inverse,
-                                 point_count, point_offset, x, y, z );
-}
-
-/************************************************************************/
-/*                             find_ctable()                            */
-/*                                                                      */
-/*    Determine which grid is the correct given an input coordinate.    */
-/************************************************************************/
-
-struct CTABLE* find_ctable(projCtx ctx, PJ_LP input, int grid_count, PJ_GRIDINFO **tables) {
-    int itable;
-
-    /* keep trying till we find a table that works */
-    for( itable = 0; itable < grid_count; itable++ )
-    {
-
-        PJ_GRIDINFO *gi = tables[itable];
-        struct CTABLE *ct = gi->ct;
-        double epsilon = (fabs(ct->del.phi)+fabs(ct->del.lam))/10000.0;
-        /* skip tables that don't match our point at all.  */
-        if ( ct->ll.phi - epsilon > input.phi
-                || ct->ll.lam - epsilon > input.lam
-                || (ct->ll.phi + (ct->lim.phi-1) * ct->del.phi + epsilon < input.phi)
-                || (ct->ll.lam + (ct->lim.lam-1) * ct->del.lam + epsilon < input.lam) ) {
-            continue;
-        }
-
-        /* If we have child nodes, check to see if any of them apply. */
-        while( gi->child )
-        {
-            PJ_GRIDINFO *child;
-
-            for( child = gi->child; child != nullptr; child = child->next )
-            {
-                struct CTABLE *ct1 = child->ct;
-                epsilon = (fabs(ct1->del.phi)+fabs(ct1->del.lam))/10000.0;
-
-                if( ct1->ll.phi - epsilon > input.phi
-                    || ct1->ll.lam - epsilon > input.lam
-                    || (ct1->ll.phi+(ct1->lim.phi-1)*ct1->del.phi + epsilon < input.phi)
-                    || (ct1->ll.lam+(ct1->lim.lam-1)*ct1->del.lam + epsilon < input.lam) ) {
-                    continue;
-                }
-                break;
-            }
-
-            /* If we didn't find a child then nothing more to do */
-            if( child == nullptr ) break;
-
-            /* Otherwise use the child, first checking it's children */
-            gi = child;
-            ct = child->ct;
-        }
-        /* load the grid shift info if we don't have it. */
-        if( ct->cvs == nullptr) {
-            if (!pj_gridinfo_load( ctx, gi ) ) {
-                pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-                return nullptr;
-            }
-        }
-        /* if we get this far we have found a suitable grid */
-        return ct;
-    }
-
-    return nullptr;
-}
-
-/************************************************************************/
-/*                        pj_apply_gridshift_3()                        */
-/*                                                                      */
-/*      This is the real workhorse, given a gridlist.                   */
-/************************************************************************/
-
-int pj_apply_gridshift_3( projCtx ctx, PJ_GRIDINFO **gridlist, int gridlist_count,
-                          int inverse, long point_count, int point_offset,
-                          double *x, double *y, double *z )
-{
-    int  i;
-    struct CTABLE *ct;
-    static int debug_count = 0;
-    (void) z;
-
-    if( gridlist== nullptr || gridlist_count == 0 )
-    {
-        pj_ctx_set_errno(ctx, PJD_ERR_FAILED_TO_LOAD_GRID);
-        return PJD_ERR_FAILED_TO_LOAD_GRID;
-    }
-
-    ctx->last_errno = 0;
-
-    for( i = 0; i < point_count; i++ )
-    {
-        long io = i * point_offset;
-        PJ_LP   input, output;
-        int  itable;
-
-        input.phi = y[io];
-        input.lam = x[io];
-        output.phi = HUGE_VAL;
-        output.lam = HUGE_VAL;
-
-        ct = find_ctable(ctx, input, gridlist_count, gridlist);
-        if( ct != nullptr )
-        {
-            output = nad_cvt( ctx, input, inverse, ct, gridlist_count, gridlist);
-
-            if ( output.lam != HUGE_VAL && debug_count++ < 20 )
-                pj_log( ctx, PJ_LOG_DEBUG_MINOR, "pj_apply_gridshift(): used %s", ct->id );
-        }
-
-        if ( output.lam == HUGE_VAL )
-        {
-            if( ctx->debug_level >= PJ_LOG_DEBUG_MAJOR )
-            {
-                pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
-                    "pj_apply_gridshift(): failed to find a grid shift table for\n"
-                    "                      location (%.7fdW,%.7fdN)",
-                    x[io] * RAD_TO_DEG,
-                    y[io] * RAD_TO_DEG );
-                for( itable = 0; itable < gridlist_count; itable++ )
-                {
-                    PJ_GRIDINFO *gi = gridlist[itable];
-                    if( itable == 0 )
-                        pj_log( ctx, PJ_LOG_DEBUG_MAJOR, "   tried: %s", gi->gridname );
-                    else
-                        pj_log( ctx, PJ_LOG_DEBUG_MAJOR, ",%s", gi->gridname );
-                }
-            }
-
-            /*
-             * We don't actually have any machinery currently to set the
-             * following macro, so this is mostly kept here to make it clear
-             * how we ought to operate if we wanted to make it super clear
-             * that an error has occurred when points are outside our available
-             * datum shift areas.  But if this is on, we will find that "low
-             * value" points on the fringes of some datasets will completely
-             * fail causing lots of problems when it is more or less ok to
-             * just not apply a datum shift.  So rather than deal with
-             * that we just fallback to no shift. (see also bug #45).
-             */
-#ifdef ERR_GRID_AREA_TRANSIENT_SEVERE
-            y[io] = HUGE_VAL;
-            x[io] = HUGE_VAL;
-#else
-            /* leave x/y unshifted. */
-#endif
-        }
-        else
-        {
-            y[io] = output.phi;
-            x[io] = output.lam;
-        }
-    }
-
-    return 0;
-}
-
-/**********************************************/
-int proj_hgrid_init(PJ* P, const char *grids) {
-/**********************************************
-
-  Initizalize and populate list of horizontal
-  grids.
-
-    Takes a PJ-object and the plus-parameter
-    name that is used in the proj-string to
-    specify the grids to load, e.g. "+grids".
-    The + should be left out here.
-
-    Returns the number of loaded grids.
-
-***********************************************/
-
-    /* prepend "s" to the "grids" string to allow usage with pj_param */
-    char *sgrids = (char *) pj_malloc( (strlen(grids)+1+1) *sizeof(char) );
-    sprintf(sgrids, "%s%s", "s", grids);
-
-    if (P->gridlist == nullptr) {
-        P->gridlist = pj_gridlist_from_nadgrids(
-            P->ctx,
-            pj_param(P->ctx, P->params, sgrids).s,
-            &(P->gridlist_count)
-        );
-
-        if( P->gridlist == nullptr || P->gridlist_count == 0 ) {
-            pj_dealloc(sgrids);
-            return 0;
-        }
-    }
-
-    if (P->gridlist_count == 0) {
-        proj_errno_set(P, PJD_ERR_FAILED_TO_LOAD_GRID);
-    }
-
-    pj_dealloc(sgrids);
-    return P->gridlist_count;
-}
-
-/********************************************/
-/*           proj_hgrid_value()             */
-/*                                          */
-/*    Return coordinate offset in grid      */
-/********************************************/
-PJ_LP proj_hgrid_value(PJ *P, PJ_LP lp) {
-    struct CTABLE *ct;
-    PJ_LP out = proj_coord_error().lp;
-
-    ct = find_ctable(P->ctx, lp, P->gridlist_count, P->gridlist);
-    if (ct == nullptr) {
-        pj_ctx_set_errno( P->ctx, PJD_ERR_GRID_AREA);
-        return out;
-    }
-
-    /* normalize input to ll origin */
-    lp.lam -= ct->ll.lam;
-    lp.phi -= ct->ll.phi;
-
-    lp.lam = adjlon(lp.lam - M_PI) + M_PI;
-
-    out = nad_intr(lp, ct);
-
-    if (out.lam == HUGE_VAL || out.phi == HUGE_VAL) {
-        pj_ctx_set_errno(P->ctx, PJD_ERR_GRID_AREA);
-    }
-
-    return out;
-}
-
-PJ_LP proj_hgrid_apply(PJ *P, PJ_LP lp, PJ_DIRECTION direction) {
-    struct CTABLE *ct;
-    int inverse;
-    PJ_LP out;
-
-    out.lam = HUGE_VAL; out.phi = HUGE_VAL;
-
-    ct = find_ctable(P->ctx, lp, P->gridlist_count, P->gridlist);
-
-    if (ct == nullptr || ct->cvs == nullptr) {
-        if( P->gridlist_count == 1 &&
-            strcmp(P->gridlist[0]->gridname, "null") == 0) {
-          // TODO: remove this particular case that is put there just to be
-          // able to handle longitudes outside of -180,180
-          out = lp;
-        } else {
-          pj_ctx_set_errno( P->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-        }
-        return out;
-    }
-
-    inverse = direction == PJ_FWD ? 0 : 1;
-    out = nad_cvt(P->ctx, lp, inverse, ct, P->gridlist_count, P->gridlist);
-
-    if (out.lam == HUGE_VAL || out.phi == HUGE_VAL)
-        pj_ctx_set_errno(P->ctx, PJD_ERR_GRID_AREA);
-
-    return out;
-
-}

src/apply_vgridshift.cpp

@@ -1,361 +0,0 @@
-/******************************************************************************
- * Project:  PROJ.4
- * Purpose:  Apply vertical datum shifts based on grid shift files, normally
- *           geoid grids mapping WGS84 to NAVD88 or something similar.
- * Author:   Frank Warmerdam, warmerdam@pobox.com
- *
- ******************************************************************************
- * Copyright (c) 2010, Frank Warmerdam <warmerdam@pobox.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *****************************************************************************/
-
-#define PJ_LIB__
-
-#include <assert.h>
-#include <stdio.h>
-#include <string.h>
-
-#include <math.h>
-#include "proj_internal.h"
-
-static int is_nodata(float value, double vmultiplier)
-{
-    /* nodata?  */
-    /* GTX official nodata value if  -88.88880f, but some grids also */
-    /* use other  big values for nodata (e.g naptrans2008.gtx has */
-    /* nodata values like -2147479936), so test them too */
-    return value * vmultiplier > 1000 || value * vmultiplier < -1000 || value == -88.88880f;
-}
-
-static double read_vgrid_value( PJ *defn, PJ_LP input, double vmultiplier, int *gridlist_count_p, PJ_GRIDINFO **tables, struct CTABLE *ct) {
-    int  itable = 0;
-    double value = HUGE_VAL;
-    double grid_x, grid_y;
-    long   grid_ix, grid_iy;
-    long   grid_ix2, grid_iy2;
-    float  *cvs;
-    /* do not deal with NaN coordinates */
-    /* cppcheck-suppress duplicateExpression */
-    if( isnan(input.phi) || isnan(input.lam) )
-        itable = *gridlist_count_p;
-
-    /* keep trying till we find a table that works */
-    for ( ; itable < *gridlist_count_p; itable++ )
-    {
-        PJ_GRIDINFO *gi = tables[itable];
-
-        ct = gi->ct;
-
-        /* skip tables that don't match our point at all (latitude check).  */
-        if( ct->ll.phi > input.phi
-            || ct->ll.phi + (ct->lim.phi-1) * ct->del.phi < input.phi )
-            continue;
-
-        bool fullWorldLongExtent = false;
-        if( fabs(ct->lim.lam * ct->del.lam - 2 * M_PI) < 1e-10 )
-        {
-            fullWorldLongExtent = true;
-        }
-
-        /* skip tables that don't match our point at all (longitude check).  */
-        else if( ct->ll.lam > input.lam
-            || ct->ll.lam + (ct->lim.lam-1) * ct->del.lam < input.lam )
-            continue;
-
-        /* If we have child nodes, check to see if any of them apply. */
-        while( gi->child != nullptr )
-        {
-            PJ_GRIDINFO *child;
-
-            for( child = gi->child; child != nullptr; child = child->next )
-            {
-                struct CTABLE *ct1 = child->ct;
-
-                fullWorldLongExtent = false;
-
-                if( ct1->ll.phi > input.phi
-                  || ct1->ll.phi+(ct1->lim.phi-1)*ct1->del.phi < input.phi)
-                    continue;
-
-                if( fabs(ct1->lim.lam * ct1->del.lam - 2 * M_PI) < 1e-10 )
-                {
-                    fullWorldLongExtent = true;
-                }
-                else if( ct1->ll.lam > input.lam
-                  || ct1->ll.lam+(ct1->lim.lam-1)*ct1->del.lam < input.lam)
-                    continue;
-
-                break;
-            }
-
-            /* we didn't find a more refined child node to use, so go with current grid */
-            if( child == nullptr )
-            {
-                break;
-            }
-
-            /* Otherwise let's try for childrens children .. */
-            gi = child;
-            ct = child->ct;
-        }
-
-        /* load the grid shift info if we don't have it. */
-        if( ct->cvs == nullptr )
-        {
-            pj_gridinfo_load( pj_get_ctx(defn), gi );
-        }
-        if( ct->cvs == nullptr )
-        {
-            pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            return PJD_ERR_FAILED_TO_LOAD_GRID;
-        }
-
-        /* Interpolation a location within the grid */
-        grid_x = (input.lam - ct->ll.lam) / ct->del.lam;
-        if( fullWorldLongExtent ) {
-            // The first fmod goes to ]-lim, lim[ range
-            // So we add lim again to be in ]0, 2*lim[ and fmod again
-            grid_x = fmod(
-                fmod(grid_x + ct->lim.lam, ct->lim.lam) + ct->lim.lam,
-                ct->lim.lam);
-        }
-        grid_y = (input.phi - ct->ll.phi) / ct->del.phi;
-        grid_ix = lround(floor(grid_x));
-        assert(grid_ix >= 0 && grid_ix < ct->lim.lam);
-        grid_iy = lround(floor(grid_y));
-        assert(grid_iy >= 0 && grid_iy < ct->lim.phi);
-        grid_x -= grid_ix;
-        grid_y -= grid_iy;
-
-        grid_ix2 = grid_ix + 1;
-        if( grid_ix2 >= ct->lim.lam ) {
-            if( fullWorldLongExtent ) {
-              grid_ix2 = 0;
-            } else {
-              grid_ix2 = ct->lim.lam - 1;
-            }
-        }
-        grid_iy2 = grid_iy + 1;
-        if( grid_iy2 >= ct->lim.phi )
-            grid_iy2 = ct->lim.phi - 1;
-
-        cvs = (float *) ct->cvs;
-        {
-            float value_a = cvs[grid_ix + grid_iy * ct->lim.lam];
-            float value_b = cvs[grid_ix2 + grid_iy * ct->lim.lam];
-            float value_c = cvs[grid_ix + grid_iy2 * ct->lim.lam];
-            float value_d = cvs[grid_ix2 + grid_iy2 * ct->lim.lam];
-            double total_weight = 0.0;
-            int n_weights = 0;
-            value = 0.0f;
-            if( !is_nodata(value_a, vmultiplier) )
-            {
-                double weight = (1.0-grid_x) * (1.0-grid_y);
-                value += value_a * weight;
-                total_weight += weight;
-                n_weights ++;
-            }
-            if( !is_nodata(value_b, vmultiplier) )
-            {
-                double weight = (grid_x) * (1.0-grid_y);
-                value += value_b * weight;
-                total_weight += weight;
-                n_weights ++;
-            }
-            if( !is_nodata(value_c, vmultiplier) )
-            {
-                double weight = (1.0-grid_x) * (grid_y);
-                value += value_c * weight;
-                total_weight += weight;
-                n_weights ++;
-            }
-            if( !is_nodata(value_d, vmultiplier) )
-            {
-                double weight = (grid_x) * (grid_y);
-                value += value_d * weight;
-                total_weight += weight;
-                n_weights ++;
-            }
-            if( n_weights == 0 )
-                value = HUGE_VAL;
-            else if( n_weights != 4 )
-                value /= total_weight;
-        }
-
-    }
-
-    return value * vmultiplier;
-}
-
-/************************************************************************/
-/*                        pj_apply_vgridshift()                         */
-/*                                                                      */
-/*      This implementation takes uses the gridlist from a coordinate   */
-/*      system definition.  If the gridlist has not yet been            */
-/*      populated in the coordinate system definition we set it up      */
-/*      now.                                                            */
-/************************************************************************/
-int pj_apply_vgridshift( PJ *defn, const char *listname,
-                         PJ_GRIDINFO ***gridlist_p,
-                         int *gridlist_count_p,
-                         int inverse,
-                         long point_count, int point_offset,
-                         double *x, double *y, double *z )
-
-{
-    int  i;
-    static int debug_count = 0;
-    PJ_GRIDINFO **tables;
-    struct CTABLE ct;
-
-    if( *gridlist_p == nullptr )
-    {
-        *gridlist_p =
-            pj_gridlist_from_nadgrids( pj_get_ctx(defn),
-                                       pj_param(defn->ctx,defn->params,listname).s,
-                                       gridlist_count_p );
-
-        if( *gridlist_p == nullptr || *gridlist_count_p == 0 )
-            return defn->ctx->last_errno;
-    }
-
-    if( *gridlist_count_p == 0 )
-    {
-        pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID);
-        return PJD_ERR_FAILED_TO_LOAD_GRID;
-    }
-
-    tables = *gridlist_p;
-    defn->ctx->last_errno = 0;
-
-    for( i = 0; i < point_count; i++ )
-    {
-        double value;
-        long io = i * point_offset;
-        PJ_LP   input;
-
-        input.phi = y[io];
-        input.lam = x[io];
-
-        value = read_vgrid_value(defn, input, 1.0, gridlist_count_p, tables, &ct);
-
-        if( inverse )
-            z[io] -= value;
-        else
-            z[io] += value;
-        if( value != HUGE_VAL )
-        {
-            if( debug_count++ < 20 ) {
-                proj_log_trace(defn, "pj_apply_gridshift(): used %s", ct.id);
-                break;
-            }
-        }
-
-        if( value == HUGE_VAL )
-        {
-            int itable;
-            std::string gridlist;
-
-            proj_log_debug(defn,
-                "pj_apply_vgridshift(): failed to find a grid shift table for\n"
-                "                       location (%.7fdW,%.7fdN)",
-                x[io] * RAD_TO_DEG,
-                y[io] * RAD_TO_DEG );
-
-            for( itable = 0; itable < *gridlist_count_p; itable++ )
-            {
-                PJ_GRIDINFO *gi = tables[itable];
-                if( itable == 0 )
-                    gridlist += "   tried: ";
-                else
-                    gridlist += ',';
-                gridlist += gi->gridname;
-            }
-
-            proj_log_debug(defn, "%s", gridlist.c_str());
-            pj_ctx_set_errno( defn->ctx, PJD_ERR_GRID_AREA );
-
-            return PJD_ERR_GRID_AREA;
-        }
-    }
-
-    return 0;
-}
-
-/**********************************************/
-int proj_vgrid_init(PJ* P, const char *grids) {
-/**********************************************
-
-  Initizalize and populate gridlist.
-
-    Takes a PJ-object and the plus-parameter
-    name that is used in the proj-string to
-    specify the grids to load, e.g. "+grids".
-    The + should be left out here.
-
-    Returns the number of loaded grids.
-
-***********************************************/
-
-    /* prepend "s" to the "grids" string to allow usage with pj_param */
-    char *sgrids = (char *) pj_malloc( (strlen(grids)+1+1) *sizeof(char) );
-    sprintf(sgrids, "%s%s", "s", grids);
-
-    if (P->vgridlist_geoid == nullptr) {
-        P->vgridlist_geoid = pj_gridlist_from_nadgrids(
-            P->ctx,
-            pj_param(P->ctx, P->params, sgrids).s,
-            &(P->vgridlist_geoid_count)
-        );
-
-        if( P->vgridlist_geoid == nullptr || P->vgridlist_geoid_count == 0 ) {
-            pj_dealloc(sgrids);
-            return 0;
-        }
-    }
-
-    if (P->vgridlist_geoid_count == 0) {
-        proj_errno_set(P, PJD_ERR_FAILED_TO_LOAD_GRID);
-    }
-
-    pj_dealloc(sgrids);
-    return P->vgridlist_geoid_count;
-}
-
-/***********************************************/
-double proj_vgrid_value(PJ *P, PJ_LP lp, double vmultiplier){
-/***********************************************
-
-  Read grid value at position lp in grids loaded
-  with proj_grid_init.
-
-  Returns the grid value of the given coordinate.
-
-************************************************/
-
-    struct CTABLE used_grid;
-    double value;
-    memset(&used_grid, 0, sizeof(struct CTABLE));
-
-    value = read_vgrid_value(P, lp, vmultiplier, &(P->vgridlist_geoid_count), P->vgridlist_geoid, &used_grid);
-    proj_log_trace(P, "proj_vgrid_value: (%f, %f) = %f", lp.lam*RAD_TO_DEG, lp.phi*RAD_TO_DEG, value);
-
-    return value;
-}

src/apps/gie.cpp

@@ -1153,6 +1153,7 @@ static const struct errno_vs_err_const lookup[] = {
     {"pjd_err_inconsistent_unit"        ,  -59},
     {"pjd_err_mutually_exclusive_args"  ,  -60},
     {"pjd_err_generic_error"            ,  -61},
+    {"pjd_err_network_error"            ,  -62},
     {"pjd_err_dont_skip"                ,  5555},
     {"pjd_err_unknown"                  ,  9999},
     {"pjd_err_enomem"                   ,  ENOMEM},

src/apps/projinfo.cpp

@@ -87,7 +87,8 @@ static void usage() {
         << "                [--spatial-test contains|intersects]" << std::endl
         << "                [--crs-extent-use none|both|intersection|smallest]"
         << std::endl
-        << "                [--grid-check none|discard_missing|sort] "
+        << "                [--grid-check "
+           "none|discard_missing|sort|known_available] "
            "[--show-superseded]"
         << std::endl
         << "                [--pivot-crs always|if_no_direct_transformation|"
@@ -554,7 +555,7 @@ static void outputObject(
     auto op = dynamic_cast<CoordinateOperation *>(obj.get());
     if (op && dbContext && getenv("PROJINFO_NO_GRID_CHECK") == nullptr) {
         try {
-            auto setGrids = op->gridsNeeded(dbContext);
+            auto setGrids = op->gridsNeeded(dbContext, false);
             bool firstWarning = true;
             for (const auto &grid : setGrids) {
                 if (!grid.available) {
@@ -570,6 +571,7 @@ static void outputObject(
                         if (!grid.url.empty()) {
                             std::cout << " at " << grid.url;
                         }
+                        std::cout << ", or on CDN";
                     } else if (!grid.url.empty()) {
                         std::cout << " Can be obtained at " << grid.url;
                     }
@@ -584,8 +586,9 @@ static void outputObject(
 
 // ---------------------------------------------------------------------------
 
-static void outputOperationSummary(const CoordinateOperationNNPtr &op,
-                                   const DatabaseContextPtr &dbContext) {
+static void outputOperationSummary(
+    const CoordinateOperationNNPtr &op, const DatabaseContextPtr &dbContext,
+    CoordinateOperationContext::GridAvailabilityUse gridAvailabilityUse) {
     auto ids = op->identifiers();
     if (!ids.empty()) {
         std::cout << *(ids[0]->codeSpace()) << ":" << ids[0]->code();
@@ -631,10 +634,16 @@ static void outputOperationSummary(const CoordinateOperationNNPtr &op,
 
     if (dbContext && getenv("PROJINFO_NO_GRID_CHECK") == nullptr) {
         try {
-            auto setGrids = op->gridsNeeded(dbContext);
+            auto setGrids = op->gridsNeeded(dbContext, false);
             for (const auto &grid : setGrids) {
                 if (!grid.available) {
                     std::cout << ", at least one grid missing";
+                    if (gridAvailabilityUse ==
+                            CoordinateOperationContext::GridAvailabilityUse::
+                                KNOWN_AVAILABLE &&
+                        !grid.packageName.empty()) {
+                        std::cout << " on the system, but available on CDN";
+                    }
                     break;
                 }
             }
@@ -731,7 +740,7 @@ static void outputOperations(
     }
     if (summary) {
         for (const auto &op : list) {
-            outputOperationSummary(op, dbContext);
+            outputOperationSummary(op, dbContext, gridAvailabilityUse);
         }
     } else {
         bool first = true;
@@ -744,7 +753,7 @@ static void outputOperations(
             std::cout << "-------------------------------------" << std::endl;
             std::cout << "Operation No. " << (i + 1) << ":" << std::endl
                       << std::endl;
-            outputOperationSummary(op, dbContext);
+            outputOperationSummary(op, dbContext, gridAvailabilityUse);
             std::cout << std::endl;
             outputObject(dbContext, op, allowUseIntermediateCRS, outputOpt);
         }
@@ -777,7 +786,9 @@ int main(int argc, char **argv) {
         CoordinateOperationContext::SourceTargetCRSExtentUse::SMALLEST;
     bool buildBoundCRSToWGS84 = false;
     CoordinateOperationContext::GridAvailabilityUse gridAvailabilityUse =
-        CoordinateOperationContext::GridAvailabilityUse::USE_FOR_SORTING;
+        pj_context_is_network_enabled(nullptr)
+            ? CoordinateOperationContext::GridAvailabilityUse::KNOWN_AVAILABLE
+            : CoordinateOperationContext::GridAvailabilityUse::USE_FOR_SORTING;
     CoordinateOperationContext::IntermediateCRSUse allowUseIntermediateCRS =
         CoordinateOperationContext::IntermediateCRSUse::
             IF_NO_DIRECT_TRANSFORMATION;
@@ -992,6 +1003,9 @@ int main(int argc, char **argv) {
             } else if (ci_equal(value, "sort")) {
                 gridAvailabilityUse = CoordinateOperationContext::
                     GridAvailabilityUse::USE_FOR_SORTING;
+            } else if (ci_equal(value, "known_available")) {
+                gridAvailabilityUse = CoordinateOperationContext::
+                    GridAvailabilityUse::KNOWN_AVAILABLE;
             } else {
                 std::cerr << "Unrecognized value for option --grid-check: "
                           << value << std::endl;

src/ctx.cpp

@@ -33,6 +33,7 @@
 
 #include "proj_experimental.h"
 #include "proj_internal.h"
+#include "filemanager.hpp"
 
 /************************************************************************/
 /*                             pj_get_ctx()                             */
@@ -60,9 +61,9 @@ void pj_set_ctx( projPJ pj, projCtx ctx )
     if (pj==nullptr)
         return;
     pj->ctx = ctx;
-    if( pj->is_pipeline )
+    if( pj->reassign_context )
     {
-        pj_pipeline_assign_context_to_steps(pj, ctx);
+        pj->reassign_context(pj, ctx);
     }
     for( const auto &alt: pj->alternativeCoordinateOperations )
     {
@@ -95,7 +96,8 @@ projCtx_t projCtx_t::createDefault()
     projCtx_t ctx;
     ctx.debug_level = PJ_LOG_NONE;
     ctx.logger = pj_stderr_logger;
-    ctx.fileapi = pj_get_default_fileapi();
+    ctx.fileapi_legacy = pj_get_default_fileapi();
+    NS_PROJ::FileManager::fillDefaultNetworkInterface(&ctx);
 
     if( getenv("PROJ_DEBUG") != nullptr )
     {
@@ -133,12 +135,13 @@ projCtx_t::projCtx_t(const projCtx_t& other)
     debug_level = other.debug_level;
     logger = other.logger;
     logger_app_data = other.logger_app_data;
-    fileapi = other.fileapi;
+    fileapi_legacy = other.fileapi_legacy;
     epsg_file_exists = other.epsg_file_exists;
     set_search_paths(other.search_paths);
     file_finder = other.file_finder;
     file_finder_legacy = other.file_finder_legacy;
     file_finder_user_data = other.file_finder_user_data;
+    networking = other.networking;
 }
 
 /************************************************************************/
@@ -258,28 +261,3 @@ void *pj_ctx_get_app_data( projCtx ctx )
         return nullptr;
     return ctx->logger_app_data;
 }
-
-/************************************************************************/
-/*                         pj_ctx_set_fileapi()                         */
-/************************************************************************/
-
-void pj_ctx_set_fileapi( projCtx ctx, projFileAPI *fileapi )
-
-{
-    if (nullptr==ctx)
-        return;
-    ctx->fileapi = fileapi;
-}
-
-/************************************************************************/
-/*                         pj_ctx_get_fileapi()                         */
-/************************************************************************/
-
-projFileAPI *pj_ctx_get_fileapi( projCtx ctx )
-
-{
-    if (nullptr==ctx)
-        return nullptr;
-    return ctx->fileapi;
-}
-

src/datum_set.cpp

@@ -41,7 +41,7 @@
 int pj_datum_set(projCtx ctx, paralist *pl, PJ *projdef)
 
 {
-    const char *name, *towgs84, *nadgrids, *catalog;
+    const char *name, *towgs84, *nadgrids;
 
     projdef->datum_type = PJD_UNKNOWN;
 
@@ -117,25 +117,6 @@ int pj_datum_set(projCtx ctx, paralist *pl, PJ *projdef)
         projdef->datum_type = PJD_GRIDSHIFT;
     }
 
-/* -------------------------------------------------------------------- */
-/*      Check for grid catalog parameter, and optional date.            */
-/* -------------------------------------------------------------------- */
-    else if( (catalog = pj_param(ctx, pl,"scatalog").s) != nullptr )
-    {
-        const char *date;
-
-        projdef->datum_type = PJD_GRIDSHIFT;
-        projdef->catalog_name = pj_strdup(catalog);
-        if (!projdef->catalog_name) {
-            pj_ctx_set_errno(ctx, ENOMEM);
-            return 1;
-        }
-
-        date = pj_param(ctx, pl, "sdate").s;
-        if( date != nullptr) 
-            projdef->datum_date = pj_gc_parsedate( ctx, date);
-    }
-
 /* -------------------------------------------------------------------- */
 /*      Check for towgs84 parameter.                                    */
 /* -------------------------------------------------------------------- */

src/fileapi.cpp

@@ -34,6 +34,7 @@
 
 #include "proj.h"
 #include "proj_internal.h"
+#include "filemanager.hpp"
 
 static PAFile stdio_fopen(projCtx ctx, const char *filename,
                              const char *access);
@@ -141,7 +142,7 @@ static void stdio_fclose(PAFile file)
 
 PAFile pj_ctx_fopen(projCtx ctx, const char *filename, const char *access)
 {
-    return ctx->fileapi->FOpen(ctx, filename, access);
+    return ctx->fileapi_legacy->FOpen(ctx, filename, access);
 }
 
 /************************************************************************/
@@ -149,7 +150,7 @@ PAFile pj_ctx_fopen(projCtx ctx, const char *filename, const char *access)
 /************************************************************************/
 size_t pj_ctx_fread(projCtx ctx, void *buffer, size_t size, size_t nmemb, PAFile file)
 {
-    return ctx->fileapi->FRead(buffer, size, nmemb, file);
+    return ctx->fileapi_legacy->FRead(buffer, size, nmemb, file);
 }
 
 /************************************************************************/
@@ -157,7 +158,7 @@ size_t pj_ctx_fread(projCtx ctx, void *buffer, size_t size, size_t nmemb, PAFile
 /************************************************************************/
 int    pj_ctx_fseek(projCtx ctx, PAFile file, long offset, int whence)
 {
-    return ctx->fileapi->FSeek(file, offset, whence);
+    return ctx->fileapi_legacy->FSeek(file, offset, whence);
 }
 
 /************************************************************************/
@@ -165,7 +166,7 @@ int    pj_ctx_fseek(projCtx ctx, PAFile file, long offset, int whence)
 /************************************************************************/
 long   pj_ctx_ftell(projCtx ctx, PAFile file)
 {
-    return ctx->fileapi->FTell(file);
+    return ctx->fileapi_legacy->FTell(file);
 }
 
 /************************************************************************/
@@ -173,7 +174,7 @@ long   pj_ctx_ftell(projCtx ctx, PAFile file)
 /************************************************************************/
 void   pj_ctx_fclose(projCtx ctx, PAFile file)
 {
-    ctx->fileapi->FClose(file);
+    ctx->fileapi_legacy->FClose(file);
 }
 
 /************************************************************************/
@@ -212,3 +213,28 @@ char *pj_ctx_fgets(projCtx ctx, char *line, int size, PAFile file)
     }
     return line;
 }
+
+/************************************************************************/
+/*                         pj_ctx_set_fileapi()                         */
+/************************************************************************/
+
+void pj_ctx_set_fileapi( projCtx ctx, projFileAPI *fileapi )
+
+{
+    if (nullptr==ctx)
+        return;
+    ctx->fileapi_legacy = fileapi;
+}
+
+/************************************************************************/
+/*                         pj_ctx_get_fileapi()                         */
+/************************************************************************/
+
+projFileAPI *pj_ctx_get_fileapi( projCtx ctx )
+
+{
+    if (nullptr==ctx)
+        return nullptr;
+    return ctx->fileapi_legacy;
+}
+

src/filemanager.hpp

@@ -0,0 +1,100 @@
+/******************************************************************************
+ * Project:  PROJ
+ * Purpose:  File manager
+ * Author:   Even Rouault, <even.rouault at spatialys.com>
+ *
+ ******************************************************************************
+ * Copyright (c) 2019, Even Rouault, <even.rouault at spatialys.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *****************************************************************************/
+
+#ifndef FILEMANAGER_HPP_INCLUDED
+#define FILEMANAGER_HPP_INCLUDED
+
+#include <memory>
+
+#include "proj.h"
+#include "proj/util.hpp"
+
+//! @cond Doxygen_Suppress
+
+NS_PROJ_START
+
+class File;
+
+enum class FileAccess {
+    READ_ONLY,   // "rb"
+    READ_UPDATE, // "r+b"
+    CREATE,      // "w+b"
+};
+
+class FileManager {
+  private:
+    FileManager() = delete;
+
+  public:
+    // "Low-level" interface.
+    static std::unique_ptr<File> open(PJ_CONTEXT *ctx, const char *filename,
+                                      FileAccess access);
+    static bool exists(PJ_CONTEXT *ctx, const char *filename);
+    static bool mkdir(PJ_CONTEXT *ctx, const char *filename);
+    static bool unlink(PJ_CONTEXT *ctx, const char *filename);
+    static bool rename(PJ_CONTEXT *ctx, const char *oldPath,
+                       const char *newPath);
+    static std::string getProjLibEnvVar(PJ_CONTEXT *ctx);
+
+    // "High-level" interface, honoring PROJ_LIB and the like.
+    static std::unique_ptr<File> open_resource_file(PJ_CONTEXT *ctx,
+                                                    const char *name);
+
+    static void fillDefaultNetworkInterface(PJ_CONTEXT *ctx);
+
+    static void clearMemoryCache();
+};
+
+// ---------------------------------------------------------------------------
+
+class File {
+  protected:
+    std::string name_;
+    explicit File(const std::string &name);
+
+  public:
+    virtual ~File();
+    virtual size_t read(void *buffer, size_t sizeBytes) = 0;
+    virtual size_t write(const void *buffer, size_t sizeBytes) = 0;
+    virtual bool seek(unsigned long long offset, int whence = SEEK_SET) = 0;
+    virtual unsigned long long tell() = 0;
+    virtual void reassign_context(PJ_CONTEXT *ctx) = 0;
+    virtual bool hasChanged() const = 0;
+
+    const std::string &name() const { return name_; }
+};
+
+// ---------------------------------------------------------------------------
+
+std::unique_ptr<File> pj_network_file_open(PJ_CONTEXT *ctx,
+                                           const char *filename);
+
+NS_PROJ_END
+
+//! @endcond Doxygen_Suppress
+
+#endif // FILEMANAGER_HPP_INCLUDED

src/gc_reader.cpp

@@ -1,248 +0,0 @@
-/******************************************************************************
- * Project:  PROJ.4
- * Purpose:  Code to read a grid catalog from a .cvs file.
- * Author:   Frank Warmerdam, warmerdam@pobox.com
- *
- ******************************************************************************
- * Copyright (c) 2012, Frank Warmerdam <warmerdam@pobox.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *****************************************************************************/
-
-#define PJ_LIB__
-
-#include <ctype.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "proj.h"
-#include "proj_internal.h"
-
-static int gc_readentry(projCtx ctx, PAFile fid, PJ_GridCatalogEntry *entry);
-
-/************************************************************************/
-/*                         pj_gc_readcatalog()                          */
-/*                                                                      */
-/*      Read a grid catalog from a .csv file.                           */
-/************************************************************************/
-
-PJ_GridCatalog *pj_gc_readcatalog( projCtx ctx, const char *catalog_name )
-{
-    PAFile fid;
-    PJ_GridCatalog *catalog;
-    int entry_max;
-    char line[302];
-
-    fid = pj_open_lib( ctx, catalog_name, "r" );
-    if (fid == nullptr) 
-        return nullptr;
-
-    /* discard title line */
-    pj_ctx_fgets(ctx, line, sizeof(line)-1, fid);
-
-    catalog = (PJ_GridCatalog *) calloc(1,sizeof(PJ_GridCatalog));
-    if( !catalog )
-    {
-        pj_ctx_set_errno(ctx, ENOMEM);
-        pj_ctx_fclose(ctx, fid);
-        return nullptr;
-    }
-    
-    catalog->catalog_name = pj_strdup(catalog_name);
-    if (!catalog->catalog_name) {
-        pj_ctx_set_errno(ctx, ENOMEM);
-        free(catalog);
-        pj_ctx_fclose(ctx, fid);
-        return nullptr;
-    }
-    
-    entry_max = 10;
-    catalog->entries = (PJ_GridCatalogEntry *) 
-        malloc(entry_max * sizeof(PJ_GridCatalogEntry));
-    if (!catalog->entries) {
-        pj_ctx_set_errno(ctx, ENOMEM);
-        free(catalog->catalog_name);
-        free(catalog);
-        pj_ctx_fclose(ctx, fid);
-        return nullptr;
-    }
-    
-    while( gc_readentry( ctx, fid, 
-                            catalog->entries+catalog->entry_count) == 0)
-    {
-        catalog->entry_count++;
-        
-        if( catalog->entry_count == entry_max ) 
-        {
-            PJ_GridCatalogEntry* new_entries;
-            entry_max = entry_max * 2;
-            new_entries = (PJ_GridCatalogEntry *) 
-                realloc(catalog->entries, 
-                        entry_max * sizeof(PJ_GridCatalogEntry));
-            if (new_entries == nullptr )
-            {
-                int i;
-                for( i = 0; i < catalog->entry_count; i++ )
-                    free( catalog->entries[i].definition );
-                free( catalog->entries );
-                free( catalog->catalog_name );
-                free( catalog );
-                pj_ctx_fclose(ctx, fid);
-                return nullptr;
-            }
-            catalog->entries = new_entries;
-        }
-    }
-
-    pj_ctx_fclose(ctx, fid);
-
-    return catalog;
-}
-
-/************************************************************************/
-/*                        gc_read_csv_line()                         */
-/*                                                                      */
-/*      Simple csv line splitter with fixed maximum line size and       */
-/*      token count.                                                    */
-/************************************************************************/
-
-static int gc_read_csv_line( projCtx ctx, PAFile fid, 
-                                char **tokens, int max_tokens ) 
-{
-    char line[302];
-   
-    while( pj_ctx_fgets(ctx, line, sizeof(line)-1, fid) != nullptr )
-    {
-        char *next = line;
-        int token_count = 0;
-        
-        while( isspace(*next) ) 
-            next++;
-        
-        /* skip blank and comment lines */
-        if( next[0] == '#' || next[0] == '\0' )
-            continue;
-        
-        while( token_count < max_tokens && *next != '\0' ) 
-        {
-            const char *start = next;
-            char* token;
-            
-            while( *next != '\0' && *next != ',' ) 
-                next++;
-            
-            if( *next == ',' )
-            {
-                *next = '\0';
-                next++;
-            }
-            
-            token = pj_strdup(start);
-            if (!token) {
-                while (token_count > 0)
-                    free(tokens[--token_count]);
-                pj_ctx_set_errno(ctx, ENOMEM);
-                return 0;
-            }
-            tokens[token_count++] = token;
-        }
-
-        return token_count;
-    }
-    
-    return 0; 
-}
-
-/************************************************************************/
-/*                          pj_gc_parsedate()                           */
-/*                                                                      */
-/*      Parse a date into a floating point year value.  Acceptable      */
-/*      values are "yyyy.fraction" and "yyyy-mm-dd".  Anything else     */
-/*      returns 0.0.                                                    */
-/************************************************************************/
-
-double pj_gc_parsedate( projCtx ctx, const char *date_string )
-{
-    (void) ctx;
-
-    if( strlen(date_string) == 10 
-        && date_string[4] == '-' && date_string[7] == '-' ) 
-    {
-        int year = atoi(date_string);
-        int month = atoi(date_string+5);
-        int day = atoi(date_string+8);
-
-        /* simplified calculation so we don't need to know all about months */
-        return year + ((month-1) * 31 + (day-1)) / 372.0;
-    }
-    else 
-    {
-        return pj_atof(date_string);
-    }
-}
-
-
-/************************************************************************/
-/*                          gc_readentry()                           */
-/*                                                                      */
-/*      Read one catalog entry from the file                            */
-/*                                                                      */
-/*      Format:                                                         */
-/*        gridname,ll_long,ll_lat,ur_long,ur_lat,priority,date          */
-/************************************************************************/
-
-static int gc_readentry(projCtx ctx, PAFile fid, PJ_GridCatalogEntry *entry) 
-{
-#define MAX_TOKENS 30
-    char *tokens[MAX_TOKENS];
-    int token_count, i;
-    int error = 0;
-
-    memset( entry, 0, sizeof(PJ_GridCatalogEntry) );
-    
-    token_count = gc_read_csv_line( ctx, fid, tokens, MAX_TOKENS );
-    if( token_count < 5 )
-    {
-        error = 1; /* TODO: need real error codes */
-        if( token_count != 0 )
-            pj_log( ctx, PJ_LOG_ERROR, "Short line in grid catalog." );
-    }
-    else
-    {
-        entry->definition = tokens[0];
-        tokens[0] = nullptr;   /* We take ownership of tokens[0] */
-        entry->region.ll_long = dmstor_ctx( ctx, tokens[1], nullptr );
-        entry->region.ll_lat = dmstor_ctx( ctx, tokens[2], nullptr );
-        entry->region.ur_long = dmstor_ctx( ctx, tokens[3], nullptr );
-        entry->region.ur_lat = dmstor_ctx( ctx, tokens[4], nullptr );
-        if( token_count > 5 )
-            entry->priority = atoi( tokens[5] ); /* defaults to zero */
-        if( token_count > 6 )
-            entry->date = pj_gc_parsedate( ctx, tokens[6] );
-    }
-
-    for( i = 0; i < token_count; i++ )
-        free( tokens[i] );
-
-    return error;
-}
-
-
-

src/gridcatalog.cpp

@@ -1,306 +0,0 @@
-/******************************************************************************
- * Project:  PROJ.4
- * Purpose:  Code in support of grid catalogs
- * Author:   Frank Warmerdam, warmerdam@pobox.com
- *
- ******************************************************************************
- * Copyright (c) 2012, Frank Warmerdam <warmerdam@pobox.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *****************************************************************************/
-
-#define PJ_LIB__
-
-#include <assert.h>
-#include <math.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "proj.h"
-#include "proj_internal.h"
-
-static PJ_GridCatalog *grid_catalog_list = nullptr;
-
-static
-PJ_GRIDINFO *pj_gc_findgrid( projCtx_t *ctx,
-                             PJ_GridCatalog *catalog, int after,
-                             PJ_LP location, double date,
-                             PJ_Region *optional_region,
-                             double *grid_date );
-
-/************************************************************************/
-/*                          pj_gc_unloadall()                           */
-/*                                                                      */
-/*      Deallocate all the grid catalogs (but not the referenced        */
-/*      grids).                                                         */
-/************************************************************************/
-
-void pj_gc_unloadall( projCtx ctx )
-{
-    (void) ctx;
-
-    while( grid_catalog_list != nullptr )
-    {
-        int i;
-        PJ_GridCatalog *catalog = grid_catalog_list;
-        grid_catalog_list = grid_catalog_list->next;
-
-        for( i = 0; i < catalog->entry_count; i++ )
-        {
-            /* we don't own gridinfo - do not free here */
-            free( catalog->entries[i].definition );
-        }
-        free( catalog->entries );
-        free( catalog->catalog_name );
-        free( catalog );
-    }
-}
-
-/************************************************************************/
-/*                         pj_gc_findcatalog()                          */
-/************************************************************************/
-
-PJ_GridCatalog *pj_gc_findcatalog( projCtx ctx, const char *name )
-
-{
-    PJ_GridCatalog *catalog;
-
-    pj_acquire_lock();
-
-    for( catalog=grid_catalog_list; catalog != nullptr; catalog = catalog->next ) 
-    {
-        if( strcmp(catalog->catalog_name, name) == 0 )
-        {
-            pj_release_lock();
-            return catalog;
-        }
-    }
-
-    pj_release_lock();
-
-    catalog = pj_gc_readcatalog( ctx, name );
-    if( catalog == nullptr )
-        return nullptr;
-
-    pj_acquire_lock();
-    catalog->next = grid_catalog_list;
-    grid_catalog_list = catalog;
-    pj_release_lock();
-
-    return catalog;
-}
-
-/************************************************************************/
-/*                       pj_gc_apply_gridshift()                        */
-/************************************************************************/
-
-int pj_gc_apply_gridshift( PJ *defn, int inverse, 
-                           long point_count, int point_offset, 
-                           double *x, double *y, double *z )
-
-{
-    int i;
-    (void) z;
-
-    if( defn->catalog == nullptr ) 
-    {
-        defn->catalog = pj_gc_findcatalog( defn->ctx, defn->catalog_name );
-        if( defn->catalog == nullptr )
-            return defn->ctx->last_errno;
-    }
-
-    defn->ctx->last_errno = 0;
-
-    for( i = 0; i < point_count; i++ )
-    {
-        long io = i * point_offset;
-        PJ_LP   input, output_after, output_before;
-        double mix_ratio;
-        PJ_GRIDINFO *gi;
-
-        input.phi = y[io];
-        input.lam = x[io];
-
-        /* make sure we have appropriate "after" shift file available */
-        if( defn->last_after_grid == nullptr
-            || input.lam < defn->last_after_region.ll_long
-            || input.lam > defn->last_after_region.ur_long
-            || input.phi < defn->last_after_region.ll_lat
-            || input.phi > defn->last_after_region.ll_lat ) {
-            defn->last_after_grid = 
-                pj_gc_findgrid( defn->ctx, defn->catalog, 
-                                1, input, defn->datum_date, 
-                                &(defn->last_after_region), 
-                                &(defn->last_after_date));
-            if( defn->last_after_grid == nullptr )
-            {
-                pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-                return PJD_ERR_FAILED_TO_LOAD_GRID;
-            }
-        }
-        gi = defn->last_after_grid;
-        assert( gi->child == nullptr );
-
-        /* load the grid shift info if we don't have it. */
-        if( gi->ct->cvs == nullptr && !pj_gridinfo_load( defn->ctx, gi ) )
-        {
-            pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            return PJD_ERR_FAILED_TO_LOAD_GRID;
-        }
-            
-        output_after = nad_cvt( defn->ctx, input, inverse, gi->ct, 0, nullptr );
-        if( output_after.lam == HUGE_VAL )
-        {
-            if( defn->ctx->debug_level >= PJ_LOG_DEBUG_MAJOR )
-            {
-                pj_log( defn->ctx, PJ_LOG_DEBUG_MAJOR,
-                        "pj_apply_gridshift(): failed to find a grid shift table for\n"
-                        "                      location (%.7fdW,%.7fdN)",
-                        x[io] * RAD_TO_DEG, 
-                        y[io] * RAD_TO_DEG );
-            }
-            continue;
-        }
-
-        if( defn->datum_date == 0.0 ) 
-        {
-            y[io] = output_after.phi;
-            x[io] = output_after.lam;
-            continue;
-        }
-
-        /* make sure we have appropriate "before" shift file available */
-        if( defn->last_before_grid == nullptr
-            || input.lam < defn->last_before_region.ll_long
-            || input.lam > defn->last_before_region.ur_long
-            || input.phi < defn->last_before_region.ll_lat
-            || input.phi > defn->last_before_region.ll_lat ) {
-            defn->last_before_grid = 
-                pj_gc_findgrid( defn->ctx, defn->catalog, 
-                                0, input, defn->datum_date, 
-                                &(defn->last_before_region), 
-                                &(defn->last_before_date));
-            if( defn->last_before_grid == nullptr )
-            {
-                pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-                return PJD_ERR_FAILED_TO_LOAD_GRID;
-            }
-        }
-
-        gi = defn->last_before_grid;
-        assert( gi->child == nullptr );
-
-        /* load the grid shift info if we don't have it. */
-        if( gi->ct->cvs == nullptr && !pj_gridinfo_load( defn->ctx, gi ) )
-        {
-            pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            return PJD_ERR_FAILED_TO_LOAD_GRID;
-        }
-            
-        output_before = nad_cvt( defn->ctx, input, inverse, gi->ct, 0, nullptr );
-        if( output_before.lam == HUGE_VAL )
-        {
-            if( defn->ctx->debug_level >= PJ_LOG_DEBUG_MAJOR )
-            {
-                pj_log( defn->ctx, PJ_LOG_DEBUG_MAJOR,
-                        "pj_apply_gridshift(): failed to find a grid shift table for\n"
-                        "                      location (%.7fdW,%.7fdN)",
-                        x[io] * RAD_TO_DEG, 
-                        y[io] * RAD_TO_DEG );
-            }
-            continue;
-        }
-
-        mix_ratio = (defn->datum_date - defn->last_before_date) 
-            / (defn->last_after_date - defn->last_before_date);
-
-        y[io] = mix_ratio * output_after.phi 
-            + (1.0-mix_ratio) * output_before.phi;
-        x[io] = mix_ratio * output_after.lam 
-            + (1.0-mix_ratio) * output_before.lam;
-    }
-
-    return 0;
-}
-
-/************************************************************************/
-/*                           pj_c_findgrid()                            */
-/************************************************************************/
-
-static
-PJ_GRIDINFO *pj_gc_findgrid( projCtx ctx, PJ_GridCatalog *catalog, int after,
-                             PJ_LP location, double date,
-                             PJ_Region *optional_region,
-                             double *grid_date ) 
-{
-    int iEntry;
-    PJ_GridCatalogEntry *entry = nullptr;
-
-    for( iEntry = 0; iEntry < catalog->entry_count; iEntry++ ) 
-    {
-        entry = catalog->entries + iEntry;
-
-        if( (after && entry->date < date) 
-            || (!after && entry->date > date) )
-            continue;
-
-        if( location.lam < entry->region.ll_long
-            || location.lam > entry->region.ur_long
-            || location.phi < entry->region.ll_lat
-            || location.phi > entry->region.ur_lat )
-            continue;
-
-        if( entry->available == -1 )
-            continue;
-
-        break;
-    }
-
-    if( entry == nullptr )
-    {
-        if( grid_date )
-            *grid_date = 0.0;
-        if( optional_region != nullptr )
-            memset( optional_region, 0, sizeof(PJ_Region));
-        return nullptr;
-    }
-
-    if( grid_date )
-        *grid_date = entry->date;
-
-    if( optional_region )
-    {
-        
-    }
-
-    if( entry->gridinfo == nullptr )
-    {
-        PJ_GRIDINFO **gridlist = nullptr;
-        int grid_count = 0;
-        gridlist = pj_gridlist_from_nadgrids( ctx, entry->definition, 
-                                              &grid_count);
-        // FIXME: this leaks gridlist itself, and memory ownership of
-        // entry->gridinfo is also confusing. Coverity CID 193539
-        if( grid_count == 1 )
-            entry->gridinfo = gridlist[0];
-    }
-    
-    return entry->gridinfo;
-}
-                             

src/gridinfo.cpp

@@ -1,988 +0,0 @@
-/******************************************************************************
- * Project:  PROJ.4
- * Purpose:  Functions for handling individual PJ_GRIDINFO's.  Includes
- *           loaders for all formats but CTABLE (in nad_init.c).
- * Author:   Frank Warmerdam, warmerdam@pobox.com
- *
- ******************************************************************************
- * Copyright (c) 2000, Frank Warmerdam <warmerdam@pobox.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *****************************************************************************/
-
-#define PJ_LIB__
-
-#include <errno.h>
-#include <math.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "proj_internal.h"
-
-/************************************************************************/
-/*                             swap_words()                             */
-/*                                                                      */
-/*      Convert the byte order of the given word(s) in place.           */
-/************************************************************************/
-
-static const int  byte_order_test = 1;
-#define IS_LSB	(1 == ((const unsigned char *) (&byte_order_test))[0])
-
-static void swap_words( unsigned char *data, int word_size, int word_count )
-
-{
-    int	word;
-
-    for( word = 0; word < word_count; word++ )
-    {
-        int	i;
-
-        for( i = 0; i < word_size/2; i++ )
-        {
-            unsigned char	t;
-
-            t = data[i];
-            data[i] = data[word_size-i-1];
-            data[word_size-i-1] = t;
-        }
-
-        data += word_size;
-    }
-}
-
-/************************************************************************/
-/*                             to_double()                              */
-/*                                                                      */
-/*      Returns a double from the pointed data.                         */
-/************************************************************************/
-
-static double to_double( unsigned char* data )
-{
-    double d;
-    memcpy(&d, data, sizeof(d));
-    return d;
-}
-
-/************************************************************************/
-/*                          pj_gridinfo_free()                          */
-/************************************************************************/
-
-void pj_gridinfo_free( projCtx ctx, PJ_GRIDINFO *gi )
-
-{
-    if( gi == nullptr )
-        return;
-
-    if( gi->child != nullptr )
-    {
-        PJ_GRIDINFO *child, *next;
-
-        for( child = gi->child; child != nullptr; child=next)
-        {
-            next=child->next;
-            pj_gridinfo_free( ctx, child );
-        }
-    }
-
-    if( gi->ct != nullptr )
-        nad_free( gi->ct );
-
-    free( gi->gridname );
-    if( gi->filename != nullptr )
-        free( gi->filename );
-
-    pj_dalloc( gi );
-}
-
-/************************************************************************/
-/*                          pj_gridinfo_load()                          */
-/*                                                                      */
-/*      This function is intended to implement delayed loading of       */
-/*      the data contents of a grid file.  The header and related       */
-/*      stuff are loaded by pj_gridinfo_init().                         */
-/************************************************************************/
-
-int pj_gridinfo_load( projCtx_t* ctx, PJ_GRIDINFO *gi )
-
-{
-    struct CTABLE ct_tmp;
-
-    if( gi == nullptr || gi->ct == nullptr )
-        return 0;
-
-    pj_acquire_lock();
-    if( gi->ct->cvs != nullptr )
-    {
-        pj_release_lock();
-        return 1;
-    }
-
-    memcpy(&ct_tmp, gi->ct, sizeof(struct CTABLE));
-
-/* -------------------------------------------------------------------- */
-/*      Original platform specific CTable format.                       */
-/* -------------------------------------------------------------------- */
-    if( strcmp(gi->format,"ctable") == 0 )
-    {
-        PAFile fid;
-        int result;
-
-        fid = pj_open_lib( ctx, gi->filename, "rb" );
-
-        if( fid == nullptr )
-        {
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            pj_release_lock();
-            return 0;
-        }
-
-        result = nad_ctable_load( ctx, &ct_tmp, (struct projFileAPI_t*)fid );
-
-        pj_ctx_fclose( ctx, fid );
-
-        gi->ct->cvs = ct_tmp.cvs;
-        pj_release_lock();
-
-        return result;
-    }
-
-/* -------------------------------------------------------------------- */
-/*      CTable2 format.                                                 */
-/* -------------------------------------------------------------------- */
-    else if( strcmp(gi->format,"ctable2") == 0 )
-    {
-        PAFile fid;
-        int result;
-
-        fid = pj_open_lib( ctx, gi->filename, "rb" );
-
-        if( fid == nullptr )
-        {
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            pj_release_lock();
-            return 0;
-        }
-
-        result = nad_ctable2_load( ctx, &ct_tmp, (struct projFileAPI_t*)fid );
-
-        pj_ctx_fclose( ctx, fid );
-
-        gi->ct->cvs = ct_tmp.cvs;
-
-        pj_release_lock();
-        return result;
-    }
-
-/* -------------------------------------------------------------------- */
-/*      NTv1 format.                                                    */
-/*      We process one line at a time.  Note that the array storage     */
-/*      direction (e-w) is different in the NTv1 file and what          */
-/*      the CTABLE is supposed to have.  The phi/lam are also           */
-/*      reversed, and we have to be aware of byte swapping.             */
-/* -------------------------------------------------------------------- */
-    else if( strcmp(gi->format,"ntv1") == 0 )
-    {
-        double	*row_buf;
-        int	row;
-        PAFile fid;
-
-        fid = pj_open_lib( ctx, gi->filename, "rb" );
-
-        if( fid == nullptr )
-        {
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            pj_release_lock();
-            return 0;
-        }
-
-        pj_ctx_fseek( ctx, fid, gi->grid_offset, SEEK_SET );
-
-        row_buf = (double *) pj_malloc(gi->ct->lim.lam * sizeof(double) * 2);
-        ct_tmp.cvs = (FLP *) pj_malloc(gi->ct->lim.lam*gi->ct->lim.phi*sizeof(FLP));
-        if( row_buf == nullptr || ct_tmp.cvs == nullptr )
-        {
-            pj_dalloc( row_buf );
-            pj_dalloc( ct_tmp.cvs );
-            pj_ctx_set_errno( ctx, ENOMEM );
-            pj_release_lock();
-            return 0;
-        }
-
-        for( row = 0; row < gi->ct->lim.phi; row++ )
-        {
-            int	    i;
-            FLP     *cvs;
-            double  *diff_seconds;
-
-            if( pj_ctx_fread( ctx, row_buf,
-                              sizeof(double), gi->ct->lim.lam * 2, fid )
-                != (size_t)( 2 * gi->ct->lim.lam ) )
-            {
-                pj_dalloc( row_buf );
-                pj_dalloc( ct_tmp.cvs );
-                pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-                pj_release_lock();
-                return 0;
-            }
-
-            if( IS_LSB )
-                swap_words( (unsigned char *) row_buf, 8, gi->ct->lim.lam*2 );
-
-            /* convert seconds to radians */
-            diff_seconds = row_buf;
-
-            for( i = 0; i < gi->ct->lim.lam; i++ )
-            {
-                cvs = ct_tmp.cvs + (row) * gi->ct->lim.lam
-                    + (gi->ct->lim.lam - i - 1);
-
-                cvs->phi = (float) (*(diff_seconds++) * ((M_PI/180.0) / 3600.0));
-                cvs->lam = (float) (*(diff_seconds++) * ((M_PI/180.0) / 3600.0));
-            }
-        }
-
-        pj_dalloc( row_buf );
-
-        pj_ctx_fclose( ctx, fid );
-
-        gi->ct->cvs = ct_tmp.cvs;
-        pj_release_lock();
-
-        return 1;
-    }
-
-/* -------------------------------------------------------------------- */
-/*      NTv2 format.                                                    */
-/*      We process one line at a time.  Note that the array storage     */
-/*      direction (e-w) is different in the NTv2 file and what          */
-/*      the CTABLE is supposed to have.  The phi/lam are also           */
-/*      reversed, and we have to be aware of byte swapping.             */
-/* -------------------------------------------------------------------- */
-    else if( strcmp(gi->format,"ntv2") == 0 )
-    {
-        float	*row_buf;
-        int	row;
-        PAFile fid;
-
-        pj_log( ctx, PJ_LOG_DEBUG_MINOR,
-                "NTv2 - loading grid %s", gi->ct->id );
-
-        fid = pj_open_lib( ctx, gi->filename, "rb" );
-
-        if( fid == nullptr )
-        {
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            pj_release_lock();
-            return 0;
-        }
-
-        pj_ctx_fseek( ctx, fid, gi->grid_offset, SEEK_SET );
-
-        row_buf = (float *) pj_malloc(gi->ct->lim.lam * sizeof(float) * 4);
-        ct_tmp.cvs = (FLP *) pj_malloc(gi->ct->lim.lam*gi->ct->lim.phi*sizeof(FLP));
-        if( row_buf == nullptr || ct_tmp.cvs == nullptr )
-        {
-            pj_dalloc( row_buf );
-            pj_dalloc( ct_tmp.cvs );
-            pj_ctx_set_errno( ctx, ENOMEM );
-            pj_release_lock();
-            return 0;
-        }
-
-        for( row = 0; row < gi->ct->lim.phi; row++ )
-        {
-            int	    i;
-            FLP     *cvs;
-            float   *diff_seconds;
-
-            if( pj_ctx_fread( ctx, row_buf, sizeof(float),
-                              gi->ct->lim.lam*4, fid )
-                != (size_t)( 4 * gi->ct->lim.lam ) )
-            {
-                pj_dalloc( row_buf );
-                pj_dalloc( ct_tmp.cvs );
-                pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-                pj_release_lock();
-                return 0;
-            }
-
-            if( gi->must_swap )
-                swap_words( (unsigned char *) row_buf, 4,
-                            gi->ct->lim.lam*4 );
-
-            /* convert seconds to radians */
-            diff_seconds = row_buf;
-
-            for( i = 0; i < gi->ct->lim.lam; i++ )
-            {
-                cvs = ct_tmp.cvs + (row) * gi->ct->lim.lam
-                    + (gi->ct->lim.lam - i - 1);
-
-                cvs->phi = (float) (*(diff_seconds++) * ((M_PI/180.0) / 3600.0));
-                cvs->lam = (float) (*(diff_seconds++) * ((M_PI/180.0) / 3600.0));
-                diff_seconds += 2; /* skip accuracy values */
-            }
-        }
-
-        pj_dalloc( row_buf );
-
-        pj_ctx_fclose( ctx, fid );
-
-        gi->ct->cvs = ct_tmp.cvs;
-
-        pj_release_lock();
-        return 1;
-    }
-
-/* -------------------------------------------------------------------- */
-/*      GTX format.                                                     */
-/* -------------------------------------------------------------------- */
-    else if( strcmp(gi->format,"gtx") == 0 )
-    {
-        int   words = gi->ct->lim.lam * gi->ct->lim.phi;
-        PAFile fid;
-
-        fid = pj_open_lib( ctx, gi->filename, "rb" );
-
-        if( fid == nullptr )
-        {
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            pj_release_lock();
-            return 0;
-        }
-
-        pj_ctx_fseek( ctx, fid, gi->grid_offset, SEEK_SET );
-
-        ct_tmp.cvs = (FLP *) pj_malloc(words*sizeof(float));
-        if( ct_tmp.cvs == nullptr )
-        {
-            pj_ctx_set_errno( ctx, ENOMEM );
-            pj_release_lock();
-            return 0;
-        }
-
-        if( pj_ctx_fread( ctx, ct_tmp.cvs, sizeof(float), words, fid )
-            != (size_t)words )
-        {
-            pj_dalloc( ct_tmp.cvs );
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            pj_release_lock();
-            return 0;
-        }
-
-        if( IS_LSB )
-            swap_words( (unsigned char *) ct_tmp.cvs, 4, words );
-
-        pj_ctx_fclose( ctx, fid );
-        gi->ct->cvs = ct_tmp.cvs;
-        pj_release_lock();
-        return 1;
-    }
-
-    else
-    {
-        pj_release_lock();
-        return 0;
-    }
-}
-
-/************************************************************************/
-/*                        gridinfo_parent()                          */
-/*                                                                      */
-/*      Seek a parent grid file by name from a grid list                */
-/************************************************************************/
-
-static PJ_GRIDINFO* gridinfo_parent( PJ_GRIDINFO *gilist,
-        const char *name, int length )
-{
-    while( gilist )
-    {
-        if( strncmp(gilist->ct->id,name,length) == 0 ) return gilist;
-        if( gilist->child )
-        {
-            PJ_GRIDINFO *parent=gridinfo_parent( gilist->child, name, length );
-            if( parent ) return parent;
-        }
-        gilist=gilist->next;
-    }
-    return gilist;
-}
-
-/************************************************************************/
-/*                       pj_gridinfo_init_ntv2()                        */
-/*                                                                      */
-/*      Load a ntv2 (.gsb) file.                                        */
-/************************************************************************/
-
-static int pj_gridinfo_init_ntv2( projCtx ctx, PAFile fid, PJ_GRIDINFO *gilist )
-{
-    unsigned char header[11*16];
-    int num_subfiles, subfile;
-    int must_swap;
-
-    /* cppcheck-suppress sizeofCalculation */
-    STATIC_ASSERT( sizeof(pj_int32) == 4 );
-    /* cppcheck-suppress sizeofCalculation */
-    STATIC_ASSERT( sizeof(double) == 8 );
-
-/* -------------------------------------------------------------------- */
-/*      Read the overview header.                                       */
-/* -------------------------------------------------------------------- */
-    if( pj_ctx_fread( ctx, header, sizeof(header), 1, fid ) != 1 )
-    {
-        pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-        return 0;
-    }
-
-    if( header[8] == 11 )
-        must_swap = !IS_LSB;
-    else
-        must_swap = IS_LSB;
-
-/* -------------------------------------------------------------------- */
-/*      Byte swap interesting fields if needed.                         */
-/* -------------------------------------------------------------------- */
-    if( must_swap )
-    {
-        swap_words( header+8, 4, 1 );
-        swap_words( header+8+16, 4, 1 );
-        swap_words( header+8+32, 4, 1 );
-        swap_words( header+8+7*16, 8, 1 );
-        swap_words( header+8+8*16, 8, 1 );
-        swap_words( header+8+9*16, 8, 1 );
-        swap_words( header+8+10*16, 8, 1 );
-    }
-
-/* -------------------------------------------------------------------- */
-/*      Get the subfile count out ... all we really use for now.        */
-/* -------------------------------------------------------------------- */
-    memcpy( &num_subfiles, header+8+32, 4 );
-
-/* ==================================================================== */
-/*      Step through the subfiles, creating a PJ_GRIDINFO for each.     */
-/* ==================================================================== */
-    for( subfile = 0; subfile < num_subfiles; subfile++ )
-    {
-        struct CTABLE *ct;
-        PJ_LP ur;
-        int gs_count;
-        PJ_GRIDINFO *gi;
-
-/* -------------------------------------------------------------------- */
-/*      Read header.                                                    */
-/* -------------------------------------------------------------------- */
-        if( pj_ctx_fread( ctx, header, sizeof(header), 1, fid ) != 1 )
-        {
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            return 0;
-        }
-
-        if( strncmp((const char *) header,"SUB_NAME",8) != 0 )
-        {
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            return 0;
-        }
-
-/* -------------------------------------------------------------------- */
-/*      Byte swap interesting fields if needed.                         */
-/* -------------------------------------------------------------------- */
-        if( must_swap )
-        {
-            swap_words( header+8+16*4, 8, 1 );
-            swap_words( header+8+16*5, 8, 1 );
-            swap_words( header+8+16*6, 8, 1 );
-            swap_words( header+8+16*7, 8, 1 );
-            swap_words( header+8+16*8, 8, 1 );
-            swap_words( header+8+16*9, 8, 1 );
-            swap_words( header+8+16*10, 4, 1 );
-        }
-
-/* -------------------------------------------------------------------- */
-/*      Initialize a corresponding "ct" structure.                      */
-/* -------------------------------------------------------------------- */
-        ct = (struct CTABLE *) pj_malloc(sizeof(struct CTABLE));
-        if (!ct) {
-            pj_ctx_set_errno(ctx, ENOMEM);
-            return 0;
-        }
-        strncpy( ct->id, (const char *) header + 8, 8 );
-        ct->id[8] = '\0';
-
-        ct->ll.lam = - to_double(header+7*16+8); /* W_LONG */
-        ct->ll.phi = to_double(header+4*16+8);   /* S_LAT */
-
-        ur.lam = - to_double(header+6*16+8);     /* E_LONG */
-        ur.phi = to_double(header+5*16+8);       /* N_LAT */
-
-        ct->del.lam = to_double(header+9*16+8);
-        ct->del.phi = to_double(header+8*16+8);
-
-        ct->lim.lam = (pj_int32) (fabs(ur.lam-ct->ll.lam)/ct->del.lam + 0.5) + 1;
-        ct->lim.phi = (pj_int32) (fabs(ur.phi-ct->ll.phi)/ct->del.phi + 0.5) + 1;
-
-        pj_log( ctx, PJ_LOG_DEBUG_MINOR,
-                "NTv2 %s %dx%d: LL=(%.9g,%.9g) UR=(%.9g,%.9g)",
-                ct->id,
-                ct->lim.lam, ct->lim.phi,
-                ct->ll.lam/3600.0, ct->ll.phi/3600.0,
-                ur.lam/3600.0, ur.phi/3600.0 );
-
-        ct->ll.lam *= DEG_TO_RAD/3600.0;
-        ct->ll.phi *= DEG_TO_RAD/3600.0;
-        ct->del.lam *= DEG_TO_RAD/3600.0;
-        ct->del.phi *= DEG_TO_RAD/3600.0;
-
-        memcpy( &gs_count, header + 8 + 16*10, 4 );
-        if( gs_count != ct->lim.lam * ct->lim.phi )
-        {
-            pj_log( ctx, PJ_LOG_ERROR,
-                    "GS_COUNT(%d) does not match expected cells (%dx%d=%d)",
-                    gs_count, ct->lim.lam, ct->lim.phi,
-                    ct->lim.lam * ct->lim.phi );
-            pj_dalloc(ct);
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            return 0;
-        }
-
-        ct->cvs = nullptr;
-
-/* -------------------------------------------------------------------- */
-/*      Create a new gridinfo for this if we aren't processing the      */
-/*      1st subfile, and initialize our grid info.                      */
-/* -------------------------------------------------------------------- */
-        if( subfile == 0 )
-            gi = gilist;
-        else
-        {
-            gi = (PJ_GRIDINFO *) pj_calloc(1, sizeof(PJ_GRIDINFO));
-            if (!gi) {
-                pj_dalloc(ct);
-                pj_gridinfo_free(ctx, gilist);
-                pj_ctx_set_errno(ctx, ENOMEM);
-                return 0;
-            }
-
-            gi->gridname = pj_strdup( gilist->gridname );
-            gi->filename = pj_strdup( gilist->filename );
-            if (!gi->gridname || !gi->filename) {
-                pj_gridinfo_free(ctx, gi);
-                pj_dalloc(ct);
-                pj_gridinfo_free(ctx, gilist);
-                pj_ctx_set_errno(ctx, ENOMEM);
-                return 0;
-            }
-            gi->next = nullptr;
-        }
-
-        gi->must_swap = must_swap;
-        gi->ct = ct;
-        gi->format = "ntv2";
-        gi->grid_offset = pj_ctx_ftell( ctx, fid );
-
-/* -------------------------------------------------------------------- */
-/*      Attach to the correct list or sublist.                          */
-/* -------------------------------------------------------------------- */
-        if( strncmp((const char *)header+24,"NONE",4) == 0 )
-        {
-            if( gi != gilist )
-            {
-                PJ_GRIDINFO *lnk;
-
-                for( lnk = gilist; lnk->next != nullptr; lnk = lnk->next ) {}
-                lnk->next = gi;
-            }
-        }
-
-        else
-        {
-            PJ_GRIDINFO *lnk;
-            PJ_GRIDINFO *gp = gridinfo_parent(gilist,
-                                                 (const char*)header+24,8);
-
-            if( gp == nullptr )
-            {
-                pj_log( ctx, PJ_LOG_ERROR,
-                        "pj_gridinfo_init_ntv2(): "
-                        "failed to find parent %8.8s for %s.",
-                        (const char *) header+24, gi->ct->id );
-
-                for( lnk = gilist; lnk->next != nullptr; lnk = lnk->next ) {}
-                lnk->next = gi;
-            }
-            else
-            {
-                if( gp->child == nullptr )
-                {
-                    gp->child = gi;
-                }
-                else
-                {
-                    for( lnk = gp->child; lnk->next != nullptr; lnk = lnk->next ) {}
-                    lnk->next = gi;
-                }
-            }
-        }
-
-/* -------------------------------------------------------------------- */
-/*      Seek past the data.                                             */
-/* -------------------------------------------------------------------- */
-        pj_ctx_fseek( ctx, fid, gs_count * 16, SEEK_CUR );
-    }
-
-    return 1;
-}
-
-/************************************************************************/
-/*                       pj_gridinfo_init_ntv1()                        */
-/*                                                                      */
-/*      Load an NTv1 style Canadian grid shift file.                    */
-/************************************************************************/
-
-static int pj_gridinfo_init_ntv1( projCtx ctx, PAFile fid, PJ_GRIDINFO *gi )
-
-{
-    unsigned char header[192]; /* 12 records of 16 bytes */
-    struct CTABLE *ct;
-    PJ_LP		ur;
-
-    /* cppcheck-suppress sizeofCalculation */
-    STATIC_ASSERT( sizeof(pj_int32) == 4 );
-    /* cppcheck-suppress sizeofCalculation */
-    STATIC_ASSERT( sizeof(double) == 8 );
-
-/* -------------------------------------------------------------------- */
-/*      Read the header.                                                */
-/* -------------------------------------------------------------------- */
-    if( pj_ctx_fread( ctx, header, sizeof(header), 1, fid ) != 1 )
-    {
-        pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-        return 0;
-    }
-
-/* -------------------------------------------------------------------- */
-/*      Regularize fields of interest.                                  */
-/* -------------------------------------------------------------------- */
-    if( IS_LSB )
-    {
-        swap_words( header+8, 4, 1 );
-        swap_words( header+24, 8, 1 );
-        swap_words( header+40, 8, 1 );
-        swap_words( header+56, 8, 1 );
-        swap_words( header+72, 8, 1 );
-        swap_words( header+88, 8, 1 );
-        swap_words( header+104, 8, 1 );
-    }
-
-    if( *((int *) (header+8)) != 12 )
-    {
-        pj_log( ctx, PJ_LOG_ERROR,
-                "NTv1 grid shift file has wrong record count, corrupt?" );
-        pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-        return 0;
-    }
-
-/* -------------------------------------------------------------------- */
-/*      Fill in CTABLE structure.                                       */
-/* -------------------------------------------------------------------- */
-    ct = (struct CTABLE *) pj_malloc(sizeof(struct CTABLE));
-    if (!ct) {
-        pj_ctx_set_errno(ctx, ENOMEM);
-        return 0;
-    }
-    strcpy( ct->id, "NTv1 Grid Shift File" );
-
-    ct->ll.lam = - to_double(header+72);
-    ct->ll.phi = to_double(header+24);
-    ur.lam = - to_double(header+56);
-    ur.phi = to_double(header+40);
-    ct->del.lam = to_double(header+104);
-    ct->del.phi = to_double(header+88);
-    ct->lim.lam = (pj_int32) (fabs(ur.lam-ct->ll.lam)/ct->del.lam + 0.5) + 1;
-    ct->lim.phi = (pj_int32) (fabs(ur.phi-ct->ll.phi)/ct->del.phi + 0.5) + 1;
-
-    pj_log( ctx, PJ_LOG_DEBUG_MINOR,
-            "NTv1 %dx%d: LL=(%.9g,%.9g) UR=(%.9g,%.9g)",
-            ct->lim.lam, ct->lim.phi,
-            ct->ll.lam, ct->ll.phi, ur.lam, ur.phi );
-
-    ct->ll.lam *= DEG_TO_RAD;
-    ct->ll.phi *= DEG_TO_RAD;
-    ct->del.lam *= DEG_TO_RAD;
-    ct->del.phi *= DEG_TO_RAD;
-    ct->cvs = nullptr;
-
-    gi->ct = ct;
-    gi->grid_offset = (long) sizeof(header);
-    gi->format = "ntv1";
-
-    return 1;
-}
-
-/************************************************************************/
-/*                       pj_gridinfo_init_gtx()                         */
-/*                                                                      */
-/*      Load a NOAA .gtx vertical datum shift file.                     */
-/************************************************************************/
-
-static int pj_gridinfo_init_gtx( projCtx ctx, PAFile fid, PJ_GRIDINFO *gi )
-
-{
-    unsigned char header[40];
-    struct CTABLE *ct;
-    double      xorigin,yorigin,xstep,ystep;
-    int         rows, columns;
-
-    /* cppcheck-suppress sizeofCalculation */
-    STATIC_ASSERT( sizeof(pj_int32) == 4 );
-    /* cppcheck-suppress sizeofCalculation */
-    STATIC_ASSERT( sizeof(double) == 8 );
-
-/* -------------------------------------------------------------------- */
-/*      Read the header.                                                */
-/* -------------------------------------------------------------------- */
-    if( pj_ctx_fread( ctx, header, sizeof(header), 1, fid ) != 1 )
-    {
-        pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-        return 0;
-    }
-
-/* -------------------------------------------------------------------- */
-/*      Regularize fields of interest and extract.                      */
-/* -------------------------------------------------------------------- */
-    if( IS_LSB )
-    {
-        swap_words( header+0, 8, 4 );
-        swap_words( header+32, 4, 2 );
-    }
-
-    memcpy( &yorigin, header+0, 8 );
-    memcpy( &xorigin, header+8, 8 );
-    memcpy( &ystep, header+16, 8 );
-    memcpy( &xstep, header+24, 8 );
-
-    memcpy( &rows, header+32, 4 );
-    memcpy( &columns, header+36, 4 );
-
-    if( xorigin < -360 || xorigin > 360
-        || yorigin < -90 || yorigin > 90 )
-    {
-        pj_log( ctx, PJ_LOG_ERROR,
-                "gtx file header has invalid extents, corrupt?");
-        pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-        return 0;
-    }
-
-/* -------------------------------------------------------------------- */
-/*      Fill in CTABLE structure.                                       */
-/* -------------------------------------------------------------------- */
-    ct = (struct CTABLE *) pj_malloc(sizeof(struct CTABLE));
-    if (!ct) {
-        pj_ctx_set_errno(ctx, ENOMEM);
-        return 0;
-    }
-    strcpy( ct->id, "GTX Vertical Grid Shift File" );
-
-    ct->ll.lam = xorigin;
-    ct->ll.phi = yorigin;
-    ct->del.lam = xstep;
-    ct->del.phi = ystep;
-    ct->lim.lam = columns;
-    ct->lim.phi = rows;
-
-    /* some GTX files come in 0-360 and we shift them back into the
-       expected -180 to 180 range if possible.  This does not solve
-       problems with grids spanning the dateline. */
-    if( ct->ll.lam >= 180.0 )
-        ct->ll.lam -= 360.0;
-
-    if( ct->ll.lam >= 0.0 && ct->ll.lam + ct->del.lam * ct->lim.lam > 180.0 )
-    {
-        pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
-                "This GTX spans the dateline!  This will cause problems." );
-    }
-
-    pj_log( ctx, PJ_LOG_DEBUG_MINOR,
-            "GTX %dx%d: LL=(%.9g,%.9g) UR=(%.9g,%.9g)",
-            ct->lim.lam, ct->lim.phi,
-            ct->ll.lam, ct->ll.phi,
-            ct->ll.lam + (columns-1)*xstep, ct->ll.phi + (rows-1)*ystep);
-
-    ct->ll.lam *= DEG_TO_RAD;
-    ct->ll.phi *= DEG_TO_RAD;
-    ct->del.lam *= DEG_TO_RAD;
-    ct->del.phi *= DEG_TO_RAD;
-    ct->cvs = nullptr;
-
-    gi->ct = ct;
-    gi->grid_offset = 40;
-    gi->format = "gtx";
-
-    return 1;
-}
-
-/************************************************************************/
-/*                          pj_gridinfo_init()                          */
-/*                                                                      */
-/*      Open and parse header details from a datum gridshift file       */
-/*      returning a list of PJ_GRIDINFOs for the grids in that          */
-/*      file.  This superceeds use of nad_init() for modern             */
-/*      applications.                                                   */
-/************************************************************************/
-
-PJ_GRIDINFO *pj_gridinfo_init( projCtx ctx, const char *gridname )
-
-{
-    PJ_GRIDINFO *gilist;
-    PAFile 	fp;
-    char	header[160];
-    size_t      header_size = 0;
-
-    errno = pj_errno = 0;
-    ctx->last_errno = 0;
-
-/* -------------------------------------------------------------------- */
-/*      Initialize a GRIDINFO with stub info we would use if it         */
-/*      cannot be loaded.                                               */
-/* -------------------------------------------------------------------- */
-    gilist = (PJ_GRIDINFO *) pj_calloc(1, sizeof(PJ_GRIDINFO));
-    if (!gilist) {
-        pj_ctx_set_errno(ctx, ENOMEM);
-        return nullptr;
-    }
-
-    gilist->gridname = pj_strdup( gridname );
-    if (!gilist->gridname) {
-        pj_dalloc(gilist);
-        pj_ctx_set_errno(ctx, ENOMEM);
-        return nullptr;
-    }
-    gilist->filename = nullptr;
-    gilist->format = "missing";
-    gilist->grid_offset = 0;
-    gilist->ct = nullptr;
-    gilist->next = nullptr;
-
-/* -------------------------------------------------------------------- */
-/*      Open the file using the usual search rules.                     */
-/* -------------------------------------------------------------------- */
-    if (!(fp = pj_open_lib(ctx, gridname, "rb"))) {
-        ctx->last_errno = 0; /* don't treat as a persistent error */
-        return gilist;
-    }
-
-    gilist->filename = pj_strdup(gridname);
-    if (!gilist->filename) {
-        pj_dalloc(gilist->gridname);
-        pj_dalloc(gilist);
-        pj_ctx_set_errno(ctx, ENOMEM);
-        return nullptr;
-    }
-
-/* -------------------------------------------------------------------- */
-/*      Load a header, to determine the file type.                      */
-/* -------------------------------------------------------------------- */
-    if( (header_size = pj_ctx_fread( ctx, header, 1,
-                                     sizeof(header), fp ) ) != sizeof(header) )
-    {
-        /* some files may be smaller that sizeof(header), eg 160, so */
-        ctx->last_errno = 0; /* don't treat as a persistent error */
-        pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
-                "pj_gridinfo_init: short header read of %d bytes",
-                (int)header_size );
-    }
-
-    pj_ctx_fseek( ctx, fp, SEEK_SET, 0 );
-
-/* -------------------------------------------------------------------- */
-/*      Determine file type.                                            */
-/* -------------------------------------------------------------------- */
-    if( header_size >= 144 + 16
-        && strncmp(header + 0, "HEADER", 6) == 0
-        && strncmp(header + 96, "W GRID", 6) == 0
-        && strncmp(header + 144, "TO      NAD83   ", 16) == 0 )
-    {
-        pj_gridinfo_init_ntv1( ctx, fp, gilist );
-    }
-
-    else if( header_size >= 48 + 7
-             && strncmp(header + 0, "NUM_OREC", 8) == 0
-             && strncmp(header + 48, "GS_TYPE", 7) == 0 )
-    {
-        pj_gridinfo_init_ntv2( ctx, fp, gilist );
-    }
-
-    else if( strlen(gridname) > 4
-             && (strcmp(gridname+strlen(gridname)-3,"gtx") == 0
-                 || strcmp(gridname+strlen(gridname)-3,"GTX") == 0) )
-    {
-        pj_gridinfo_init_gtx( ctx, fp, gilist );
-    }
-
-    else if( header_size >= 9 && strncmp(header + 0,"CTABLE V2",9) == 0 )
-    {
-        struct CTABLE *ct = nad_ctable2_init( ctx, (struct projFileAPI_t*)fp );
-
-        gilist->format = "ctable2";
-        gilist->ct = ct;
-
-        if (ct == nullptr)
-        {
-            pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
-                    "CTABLE V2 ct is NULL.");
-        }
-        else
-        {
-            pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
-                    "Ctable2 %s %dx%d: LL=(%.9g,%.9g) UR=(%.9g,%.9g)",
-                    ct->id,
-                    ct->lim.lam, ct->lim.phi,
-                    ct->ll.lam * RAD_TO_DEG, ct->ll.phi * RAD_TO_DEG,
-                    (ct->ll.lam + (ct->lim.lam-1)*ct->del.lam) * RAD_TO_DEG,
-                    (ct->ll.phi + (ct->lim.phi-1)*ct->del.phi) * RAD_TO_DEG );
-        }
-    }
-
-    else
-    {
-        struct CTABLE *ct = nad_ctable_init( ctx, (struct projFileAPI_t*)fp );
-        if (ct == nullptr)
-        {
-            pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
-                    "CTABLE ct is NULL.");
-        } else
-        {
-            gilist->format = "ctable";
-            gilist->ct = ct;
-
-            pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
-                    "Ctable %s %dx%d: LL=(%.9g,%.9g) UR=(%.9g,%.9g)",
-                    ct->id,
-                    ct->lim.lam, ct->lim.phi,
-                    ct->ll.lam * RAD_TO_DEG, ct->ll.phi * RAD_TO_DEG,
-                    (ct->ll.lam + (ct->lim.lam-1)*ct->del.lam) * RAD_TO_DEG,
-                    (ct->ll.phi + (ct->lim.phi-1)*ct->del.phi) * RAD_TO_DEG );
-        }
-    }
-
-    pj_ctx_fclose(ctx, fp);
-
-    return gilist;
-}

src/gridlist.cpp

@@ -1,220 +0,0 @@
-/******************************************************************************
- * Project:  PROJ.4
- * Purpose:  Code to manage the list of currently loaded (cached) PJ_GRIDINFOs
- *           See pj_gridinfo.c for details of loading individual grids.
- * Author:   Frank Warmerdam, warmerdam@pobox.com
- *
- ******************************************************************************
- * Copyright (c) 2000, Frank Warmerdam <warmerdam@pobox.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *****************************************************************************/
-
-#define PJ_LIB__
-
-#include <errno.h>
-#include <stddef.h>
-#include <string.h>
-
-#include "proj.h"
-#include "proj_internal.h"
-
-static PJ_GRIDINFO *grid_list = nullptr;
-#define PJ_MAX_PATH_LENGTH 1024
-
-/************************************************************************/
-/*                        pj_deallocate_grids()                         */
-/*                                                                      */
-/*      Deallocate all loaded grids.                                    */
-/************************************************************************/
-
-void pj_deallocate_grids()
-
-{
-    while( grid_list != nullptr )
-    {
-        PJ_GRIDINFO *item = grid_list;
-        grid_list = grid_list->next;
-        item->next = nullptr;
-
-        pj_gridinfo_free( pj_get_default_ctx(), item );
-    }
-}
-
-/************************************************************************/
-/*                       pj_gridlist_merge_grid()                       */
-/*                                                                      */
-/*      Find/load the named gridfile and merge it into the              */
-/*      last_nadgrids_list.                                             */
-/************************************************************************/
-
-static int pj_gridlist_merge_gridfile( projCtx ctx, 
-                                       const char *gridname,
-                                       PJ_GRIDINFO ***p_gridlist,
-                                       int *p_gridcount, 
-                                       int *p_gridmax )
-
-{
-    int got_match=0;
-    PJ_GRIDINFO *this_grid, *tail = nullptr;
-
-/* -------------------------------------------------------------------- */
-/*      Try to find in the existing list of loaded grids.  Add all      */
-/*      matching grids as with NTv2 we can get many grids from one      */
-/*      file (one shared gridname).                                     */
-/* -------------------------------------------------------------------- */
-    for( this_grid = grid_list; this_grid != nullptr; this_grid = this_grid->next)
-    {
-        if( strcmp(this_grid->gridname,gridname) == 0 )
-        {
-            got_match = 1;
-
-            /* don't add to the list if it is invalid. */
-            if( this_grid->ct == nullptr )
-                return 0;
-
-            /* do we need to grow the list? */
-            if( *p_gridcount >= *p_gridmax - 2 )
-            {
-                PJ_GRIDINFO **new_list;
-                int new_max = *p_gridmax + 20;
-
-                new_list = (PJ_GRIDINFO **) pj_calloc(new_max, sizeof(void *));
-                if (!new_list) {
-                    pj_ctx_set_errno( ctx, ENOMEM );
-                    return 0;
-                }
-                if( *p_gridlist != nullptr )
-                {
-                    memcpy( new_list, *p_gridlist,
-                            sizeof(void *) * (*p_gridmax) );
-                    pj_dalloc( *p_gridlist );
-                }
-
-                *p_gridlist = new_list;
-                *p_gridmax = new_max;
-            }
-
-            /* add to the list */
-            (*p_gridlist)[(*p_gridcount)++] = this_grid;
-            (*p_gridlist)[*p_gridcount] = nullptr;
-        }
-
-        tail = this_grid;
-    }
-
-    if( got_match )
-        return 1;
-
-/* -------------------------------------------------------------------- */
-/*      Try to load the named grid.                                     */
-/* -------------------------------------------------------------------- */
-    this_grid = pj_gridinfo_init( ctx, gridname );
-
-    if( this_grid == nullptr )
-    {
-        return 0;
-    }
-    
-    if( tail != nullptr )
-        tail->next = this_grid;
-    else
-        grid_list = this_grid;
-
-/* -------------------------------------------------------------------- */
-/*      Recurse to add the grid now that it is loaded.                  */
-/* -------------------------------------------------------------------- */
-    return pj_gridlist_merge_gridfile( ctx, gridname, p_gridlist, 
-                                       p_gridcount, p_gridmax );
-}
-
-/************************************************************************/
-/*                     pj_gridlist_from_nadgrids()                      */
-/*                                                                      */
-/*      This functions loads the list of grids corresponding to a       */
-/*      particular nadgrids string into a list, and returns it.  The    */
-/*      list is kept around till a request is made with a different     */
-/*      string in order to cut down on the string parsing cost, and     */
-/*      the cost of building the list of tables each time.              */
-/************************************************************************/
-
-PJ_GRIDINFO **pj_gridlist_from_nadgrids( projCtx ctx, const char *nadgrids, 
-                                         int *grid_count)
-
-{
-    const char *s;
-    PJ_GRIDINFO **gridlist = nullptr;
-    int grid_max = 0;
-
-    pj_errno = 0;
-    *grid_count = 0;
-
-    pj_acquire_lock();
-
-/* -------------------------------------------------------------------- */
-/*      Loop processing names out of nadgrids one at a time.            */
-/* -------------------------------------------------------------------- */
-    for( s = nadgrids; *s != '\0'; )
-    {
-        size_t end_char;
-        int    required = 1;
-        char   name[PJ_MAX_PATH_LENGTH];
-
-        if( *s == '@' )
-        {
-            required = 0;
-            s++;
-        }
-
-        for( end_char = 0; 
-             s[end_char] != '\0' && s[end_char] != ','; 
-             end_char++ ) {}
-
-        if( end_char >= sizeof(name) )
-        {
-            pj_dalloc( gridlist );
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            pj_release_lock();
-            return nullptr;
-        }
-        
-        strncpy( name, s, end_char );
-        name[end_char] = '\0';
-
-        s += end_char;
-        if( *s == ',' )
-            s++;
-
-        if( !pj_gridlist_merge_gridfile( ctx, name, &gridlist, grid_count, 
-                                         &grid_max) 
-            && required )
-        {
-            pj_dalloc( gridlist );
-            pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-            pj_release_lock();
-            return nullptr;
-        }
-        else
-            pj_errno = 0;
-    }
-
-    pj_release_lock();
-
-    return gridlist;
-}