OSGeo · rouault · Nov 9, 2025 · Nov 14, 2025
diff --git a/.github/workflows/fedora_rawhide/start.sh b/.github/workflows/fedora_rawhide/start.sh
@@ -26,8 +26,10 @@ ctest -j$(nproc)
 
 # Try EMBED_RESOURCE_DIRECTORY option
 wget https://raw.githubusercontent.com/OSGeo/PROJ-data/refs/heads/master/us_nga/us_nga_egm96_15.tif
+wget https://cdn.proj.org/fi_nls_ykj_etrs35fin.gpkg
 mkdir grids
 mv us_nga_egm96_15.tif grids
+mv fi_nls_ykj_etrs35fin.gpkg grids
 echo "Build with -DEMBED_RESOURCE_FILES=ON -DEMBED_RESOURCE_DIRECTORY=$PWD/grids"
 CC=clang CXX=clang++ cmake .. -DEMBED_RESOURCE_DIRECTORY=$PWD/grids
 make -j$(nproc)
@@ -36,6 +38,8 @@ echo 49 2 0 | bin/cs2cs "WGS84 + EGM96 height" EPSG:4979
 echo 49 2 0 | bin/cs2cs "WGS84 + EGM96 height" EPSG:4979  | grep 44.643 >/dev/null || (echo "Expected 49dN 2dE 44.643 as a result" && /bin/false)
 echo 0 0 0 | bin/cct +init=ITRF2000:ITRF96
 echo 0 0 0 | bin/cct +init=ITRF2000:ITRF96 | grep 0.0067 >/dev/null || (echo "Expected 0.0067 0.0061 -0.0185 as a result" && /bin/false)
+echo 3432087 6995748 0 | bin/cct +proj=tinshift +file=fi_nls_ykj_etrs35fin.gpkg
+echo 3432087 6995748 0 | bin/cct +proj=tinshift +file=fi_nls_ykj_etrs35fin.gpkg | grep 431943.0905 >/dev/null || (echo "Expected 431943.0905   6992816.7826 0 as a result" && /bin/false)
 
 echo "Build with -DEMBED_RESOURCE_FILES=ON -DEMBED_RESOURCE_DIRECTORY=$PWD/grids -DUSE_ONLY_EMBEDDED_RESOURCE_FILES=ON"
 CC=clang CXX=clang++ cmake .. -DEMBED_RESOURCE_DIRECTORY=$PWD/grids -DUSE_ONLY_EMBEDDED_RESOURCE_FILES=ON

diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
@@ -55,7 +55,7 @@ jobs:
         shell: cmd
         if: steps.cache.outputs.cache-hit != 'true'
         run: |
-            vcpkg install sqlite3[core,tool] tiff curl --triplet=${{ env.ARCH }}-windows
+            vcpkg install sqlite3[core,tool,rtree] tiff curl --triplet=${{ env.ARCH }}-windows
 
       - name: Build
         shell: cmd

diff --git a/data/CMakeLists.txt b/data/CMakeLists.txt
@@ -31,7 +31,7 @@ set(ALL_SQL_IN "${CMAKE_CURRENT_BINARY_DIR}/all.sql.in")
 set(PROJ_DB "${CMAKE_CURRENT_BINARY_DIR}/proj.db")
 include(sql_filelist.cmake)
 
-set(PROJ_DB_SQL_EXPECTED_MD5 "cca51e9e250f9c979e8f18bb483433e5")
+set(PROJ_DB_SQL_EXPECTED_MD5 "a71b63a199da368414be93d819bf2e5b")
 
 add_custom_command(
   OUTPUT ${PROJ_DB}

diff --git a/data/sql/grid_alternatives.sql b/data/sql/grid_alternatives.sql
@@ -183,6 +183,9 @@ VALUES
 ('fi_nls_n43_n60.json','fi_nls_n43_n60.json',NULL,'JSON','tinshift',0,NULL,'https://cdn.proj.org/fi_nls_n43_n60.json',1,1,NULL),
 ('fi_nls_n60_n2000.json','fi_nls_n60_n2000.json',NULL,'JSON','tinshift',0,NULL,'https://cdn.proj.org/fi_nls_n60_n2000.json',1,1,NULL),
 ('fi_nls_ykj_etrs35fin.json','fi_nls_ykj_etrs35fin.json',NULL,'JSON','tinshift',0,NULL,'https://cdn.proj.org/fi_nls_ykj_etrs35fin.json',1,1,NULL),
+('NOT-YET-IN-GRID-TRANSFORMATION-fi_nls_n43_n60.gpkg','fi_nls_n43_n60.gpkg',NULL,'GPKG','tinshift',0,NULL,'https://cdn.proj.org/fi_nls_n43_n60.gpkg',1,1,NULL),
+('NOT-YET-IN-GRID-TRANSFORMATION-fi_nls_n60_n2000.gpkg','fi_nls_n60_n2000.gpkg',NULL,'GPKG','tinshift',0,NULL,'https://cdn.proj.org/fi_nls_n60_n2000.gpkg',1,1,NULL),
+('NOT-YET-IN-GRID-TRANSFORMATION-fi_nls_ykj_etrs35fin.gpkg','fi_nls_ykj_etrs35fin.gpkg',NULL,'GPKG','tinshift',0,NULL,'https://cdn.proj.org/fi_nls_ykj_etrs35fin.gpkg',1,1,NULL),
 
 -- fr_ign - IGN France
 ('rgf93_ntf.gsb','fr_ign_ntf_r93.tif','ntf_r93.gsb','GTiff','hgridshift',1,NULL,'https://cdn.proj.org/fr_ign_ntf_r93.tif',1,1,NULL),

diff --git a/data/sql/proj_db_table_defs.sql b/data/sql/proj_db_table_defs.sql
@@ -896,7 +896,7 @@ CREATE TABLE grid_alternatives(
     original_grid_name TEXT NOT NULL PRIMARY KEY,   -- original grid name (e.g. Und_min2.5x2.5_egm2008_isw=82_WGS84_TideFree.gz). For LOS/LAS format, the .las files
     proj_grid_name TEXT NOT NULL,                   -- PROJ >= 7 grid name (e.g us_nga_egm08_25.tif)
     old_proj_grid_name TEXT,                        -- PROJ < 7 grid name (e.g egm08_25.gtx)
-    proj_grid_format TEXT NOT NULL,                 -- 'GTiff', 'GTX', 'NTv2', JSON
+    proj_grid_format TEXT NOT NULL,                 -- 'GTiff', 'GTX', 'NTv2', 'JSON', 'GPKG'
     proj_method TEXT NOT NULL,                      -- gridshift, hgridshift, vgridshift, geoid_like, geocentricoffset, tinshift or velocity_grid
     inverse_direction BOOLEAN NOT NULL CHECK (inverse_direction IN (0, 1)), -- whether the PROJ grid direction is reversed w.r.t to the authority one (TRUE in that case)
     package_name TEXT,                              -- no longer used. Must be NULL
@@ -906,14 +906,14 @@ CREATE TABLE grid_alternatives(
     directory TEXT,                                 -- optional directory where the file might be located
 
     CONSTRAINT fk_grid_alternatives_grid_packages FOREIGN KEY (package_name) REFERENCES grid_packages(package_name) ON DELETE CASCADE,
-    CONSTRAINT check_grid_alternatives_grid_fromat CHECK (proj_grid_format IN ('GTiff', 'GTX', 'NTv2', 'JSON')),
+    CONSTRAINT check_grid_alternatives_grid_fromat CHECK (proj_grid_format IN ('GTiff', 'GTX', 'NTv2', 'JSON', 'GPKG')),
     CONSTRAINT check_grid_alternatives_proj_method CHECK (proj_method IN ('gridshift', 'hgridshift', 'vgridshift', 'geoid_like', 'geocentricoffset', 'tinshift', 'velocity_grid', 'defmodel')),
     CONSTRAINT check_grid_alternatives_inverse_direction CHECK (NOT(proj_method = 'geoid_like' AND inverse_direction = 1)),
     CONSTRAINT check_grid_alternatives_package_name CHECK (package_name IS NULL),
     CONSTRAINT check_grid_alternatives_direct_download_url CHECK (NOT(direct_download IS NULL AND url IS NOT NULL)),
     CONSTRAINT check_grid_alternatives_open_license_url CHECK (NOT(open_license IS NULL AND url IS NOT NULL)),
     CONSTRAINT check_grid_alternatives_constraint_cdn CHECK (NOT(url LIKE 'https://cdn.proj.org/%' AND (direct_download = 0 OR open_license = 0 OR url != 'https://cdn.proj.org/' || proj_grid_name))),
-    CONSTRAINT check_grid_alternatives_tinshift CHECK ((proj_grid_format != 'JSON' AND proj_method != 'tinshift') OR (proj_grid_format = 'JSON' AND proj_method = 'tinshift'))
+    CONSTRAINT check_grid_alternatives_tinshift CHECK ((proj_grid_format NOT IN ('JSON','GPKG') AND proj_method != 'tinshift') OR (proj_grid_format IN ('JSON', 'GPKG') AND proj_method = 'tinshift'))
 ) WITHOUT ROWID;
 
 CREATE INDEX idx_grid_alternatives_proj_grid_name ON grid_alternatives(proj_grid_name);

diff --git a/data/tests/tinshift_crs_implicit.gpkg b/data/tests/tinshift_crs_implicit.gpkg
diff --git a/data/tests/tinshift_empty_file.gpkg b/data/tests/tinshift_empty_file.gpkg
diff --git a/data/tests/tinshift_fallback_nearest_centroid.gpkg b/data/tests/tinshift_fallback_nearest_centroid.gpkg
diff --git a/data/tests/tinshift_fallback_nearest_side.gpkg b/data/tests/tinshift_fallback_nearest_side.gpkg
diff --git a/data/tests/tinshift_simplified_kkj_etrs.gpkg b/data/tests/tinshift_simplified_kkj_etrs.gpkg
diff --git a/data/tests/tinshift_simplified_n60_n2000.gpkg b/data/tests/tinshift_simplified_n60_n2000.gpkg
diff --git a/docs/source/install.rst b/docs/source/install.rst
@@ -459,7 +459,7 @@ All cached entries can be viewed using ``cmake -LAH`` from a build directory.
 
     .. versionadded:: 9.6
 
-    Embed files from <directory> ending with .tif, .json or .pol in the PROJ library itself.
+    Embed files from <directory> ending with .tif, .json, .gpkg or .pol in the PROJ library itself.
 
     The pointed directory can potentially be the full PROJ-data package (uncompressed).
     In that case, about 6 GB of free disk and 16 GB of RAM are required to build PROJ.
@@ -604,3 +604,8 @@ Run PROJ tests
     cd c:\dev\PROJ
     cd _build.vs2019
     ctest -V --build-config Release
+
+
+.. spelling:word-list::
+
+    gpkg
diff --git a/docs/source/operations/transformations/tinshift.rst b/docs/source/operations/transformations/tinshift.rst
@@ -20,10 +20,11 @@ Triangulated Irregular Network based transformation
 
 
 The ``tinshift`` transformation takes one mandatory
-argument, ``file``, that points to a JSON file, which contains the
+argument, ``file``, that points to a :ref:`TIN JSON <tin_json>` or
+:ref:`TIN GeoPackage <tin_gpkg>` file, which contains the
 triangulation and associated metadata. Input and output coordinates must be
 geographic or projected coordinates.
-Depending on the content of the JSON file, horizontal, vertical or both
+Depending on the content of the TIN file, horizontal, vertical or both
 components of the coordinates may be transformed.
 
 The transformation is invertible, with the same computational complexity than
@@ -37,7 +38,7 @@ Required
 
 .. option:: +file=<filename>
 
-    Filename to the JSON file for the TIN.
+    Filename or URL to the JSON or GeoPackage file for the TIN.
 
 
 Example
@@ -116,100 +117,14 @@ the inverse transformation), otherwise which triangle will be selected is
 unspecified. Besides that, the triangulation does not need to have particular
 properties (like being a Delaunay triangulation)
 
-File format
-+++++++++++
-
-The triangulation is stored in a text-based format, using JSON as a serialization.
-
-Below a minimal example, from the KKJ to ETRS89 transformation, with just a
-single triangle:
-
-.. literalinclude:: ../../../../data/tests/tinshift_crs_implicit.json
-  :language: json
-
-
-So after the generic metadata, we define the input and output CRS (informative
-only), and that the transformation affects horizontal components of
-coordinates. We name the columns of the ``vertices`` and ``triangles`` arrays.
-We defined the source and target coordinates of each vertex, and define a
-triangle by referring to the index of its vertices in the ``vertices`` array.
-
-More formally, the specific items for the triangulation file are:
-
-input_crs
-  String identifying the CRS of source coordinates
-  in the vertices. Typically ``EPSG:XXXX``. If the transformation is for vertical
-  component, this should be the code for a compound CRS (can be EPSG:XXXX+YYYY
-  where XXXX is the code of the horizontal CRS and YYYY the code of the vertical CRS).
-  For example, for the KKJ->ETRS89 transformation, this is EPSG:2393
-  (``KKJ / Finland Uniform Coordinate System``). The input coordinates are assumed
-  to be passed in the "normalized for visualisation" / "GIS friendly" order,
-  that is longitude, latitude for geographic coordinates and
-  easting, northing for projected coordinates.
-
-
-output_crs
-  String identifying the CRS of target coordinates in the vertices.
-  Typically ``EPSG:XXXX``. If the transformation is for vertical component,
-  this should be the code for a compound CRS (can be EPSG:XXXX+YYYY where
-  XXXX is the code of the horizontal CRS and YYYY the code of the vertical CRS).
-  For example, for the KKJ->ETRS89 transformation, this is EPSG:3067
-  (\"ETRS89 / TM35FIN(E,N)\"). The output coordinates will be returned in
-  the "normalized for visualisation" / "GIS friendly" order,
-  that is longitude, latitude for geographic coordinates and
-  easting, northing for projected coordinates.
-
-
-transformed_components
-  Array which may contain one or two strings: "horizontal" when horizontal
-  components of the coordinates are transformed and/or "vertical" when the
-  vertical component is transformed.
-
-
-fallback_strategy
-  String identifying how to treat points that do not fall into any of the
-  specified triangles. This item is available for ``format_version`` >= 1.1.
-  Possible values are ``none``, ``nearest_side`` and ``nearest_centroid``. The
-  default is ``none`` and signifies, that points that fall outside the
-  specified triangles are not transformed. This is also the behavior for
-  ``format_version`` before 1.1. If ``fallback_strategy`` is set to
-  ``nearest_side``, then points that do not fall into any triangle are 
-  transformed according to the triangle closest to them by euclidean distance.
-  If ``fallback_strategy`` is set to ``nearest_centroid``, then points that do
-  not fall into any triangle are transformed according to the triangle with the
-  closest centroid (intersection of its medians).
-
-
-vertices_columns
-  Specify the name of the columns of the rows in the ``vertices``
-  array. There must be exactly as many elements in ``vertices_columns`` as in a
-  row of ``vertices``. The following names have a special meaning: ``source_x``,
-  ``source_y``, ``target_x``, ``target_y``, ``source_z``, ``target_z`` and
-  ``offset_z``.  ``source_x`` and ``source_y`` are compulsory.
-  ``source_x`` is for the source longitude (in degree) or easting.
-  ``source_y`` is for the source latitude (in degree) or northing. 
-  ``target_x`` and ``target_y`` are compulsory when ``horizontal`` is specified
-  in ``transformed_components``. (``source_z`` and ``target_z``) or
-  ``offset_z`` are compulsory when ``vertical`` is specified in ``transformed_components``
-
-
-triangles_columns
-  Specify the name of the columns of the rows in the
-  ``triangles`` array. There must be exactly as many elements in ``triangles_columns``
-  as in a row of ``triangles``. The following names have a special meaning:
-  ``idx_vertex1``, ``idx_vertex2``, ``idx_vertex3``. They are compulsory.
-
-
-vertices
-  An array whose items are themselves arrays with as many columns as
-  described in ``vertices_columns``.
-
-
-triangles
-  An array whose items are themselves arrays with as many columns as
-  described in ``triangles_columns``.
-  The value of the ``idx_vertexN`` columns must be indices
-  (between 0 and len(``vertices``-1) of items of the ``vertices`` array.
-
-A `JSON schema <https://proj.org/schemas/triangulation.schema.json>`_ is available
-for this file format.
+JSON TIN File format
+++++++++++++++++++++
+
+See :ref:`tin_json`.
+
+GeoPackage TIN File format
+++++++++++++++++++++++++++
+
+.. versionadded:: 9.8.0
+
+See :ref:`tin_gpkg`.
diff --git a/docs/source/specifications/index.rst b/docs/source/specifications/index.rst
@@ -12,3 +12,6 @@ for the sake of broader interoperability.
 
    projjson
    geodetictiffgrids
+   tin_gpkg
+   tin_json
+