[gdal-dev] gdaladdo does not "respect" GPKG tile matrix

Philippe Ghesquiere philippe.ghesquiere at airbus.com
Mon Jan 8 05:24:19 PST 2024


Hi Even,

This is great news ! I will check it out as soon as I can.
Thanks
Philippe

On Mon, Jan 8, 2024 at 1:07 PM Even Rouault <even.rouault at spatialys.com>
wrote:

> Hi Philippe,
>
> I no longer reproduce the below issues nor
> https://github.com/OSGeo/gdal/issues/3853 with gdaladdo without explicit
> level with GDAL master 3.9dev. This is due to improvement
> https://github.com/OSGeo/gdal/commit/d178b03e3db that reuse existing
> overview levels when they are declared by the dataset. Which is the case
> for a GeoPackage created with a tiling_scheme and with unpopulated levels.
>
> The only case now where the tiling scheme might no longer be respected is
> if the user specifies an overview level beyond the base one, or some
> "weird" factor like 3. But as it is the user that requests that, I don't
> think we should do anything for that case.
>
> Even
> Le 08/01/2024 à 11:57, Philippe Ghesquiere via gdal-dev a écrit :
>
> Dear all,
>  A while ago, I opened a ticket which is still opened (
> https://github.com/OSGeo/gdal/issues/3853). I recently  bumped into this
> bug with some new data, and I think I tracked the origin.
>
>
> *1) Generate a test image :*
> gdal_create -of GTIFF -co COMPRESS=LZW -a_srs epsg:4326 -a_ullr -180 90
> 180 -90 -burn 128 -outsize 2048 1024 worldwide.tif
>
> *2) Convert to GPKG :*
>  gdal_translate -of GPKG -co TILING_SCHEME=InspireCRS84Quad worldwide.tif
> worldwide_no_pyramid.gpkg
>
> The GPKG tile matrix is as expected :
> sqlite3 -header -column worldwide_no_pyramid.gpkg "SELECT rowid,* FROM
> gpkg_tile_matrix  ;"
> rowid  table_name            zoom_level  matrix_width  matrix_height
>  tile_width  tile_height  pixel_x_size  pixel_y_size
> -----  --------------------  ----------  ------------  -------------
>  ----------  -----------  ------------  ------------
> 1      worldwide_no_pyramid  0           2             1              256
>         256          0.703125      0.703125
> 2      worldwide_no_pyramid  1           4             2              256
>         256          0.3515625     0.3515625
> 3      worldwide_no_pyramid  2           8             4              256
>         256          0.17578125    0.17578125
>
> *3) Compute a default pyramid:*
> cp worldwide_no_pyramid.gpkg worldwide_default_pyramid.gpkg
> gdaladdo worldwide_default_pyramid.gpkg
>
> The GPKG tile matrix is no longer the expected one (InspireCRS84Quad
> InspireCRS84Quad) :
> sqlite3 -header -column worldwide_default_pyramid.gpkg  "SELECT rowid,*
> FROM gpkg_tile_matrix  ;"
> rowid  table_name            zoom_level  matrix_width  matrix_height
>  tile_width  tile_height  pixel_x_size  pixel_y_size
> -----  --------------------  ----------  ------------  -------------
>  ----------  -----------  ------------  ------------
> 1      worldwide_no_pyramid  1           2             1              256
>         256          0.703125      0.703125
> 2      worldwide_no_pyramid  2           4             2              256
>         256          0.3515625     0.3515625
> 3      worldwide_no_pyramid  3           8             4              256
>         256          0.17578125    0.17578125
> 4      worldwide_no_pyramid  0           1             1              256
>         256          1.40625       1.40625
>
> *4) Compute a manual pyramid:*
> cp worldwide_no_pyramid.gpkg worldwide_manual_pyramid.gpkg
> gdaladdo worldwide_manual_pyramid.gpkg 2 4
>
> The GPKG tile matrix is still as expected (InspireCRS84Quad
> InspireCRS84Quad) :
> sqlite3 -header -column worldwide_manual_pyramid.gpkg  "SELECT rowid,*
> FROM gpkg_tile_matrix  ;"
> rowid  table_name            zoom_level  matrix_width  matrix_height
>  tile_width  tile_height  pixel_x_size  pixel_y_size
> -----  --------------------  ----------  ------------  -------------
>  ----------  -----------  ------------  ------------
> 1      worldwide_no_pyramid  0           2             1              256
>         256          0.703125      0.703125
> 2      worldwide_no_pyramid  1           4             2              256
>         256          0.3515625     0.3515625
> 3      worldwide_no_pyramid  2           8             4              256
>         256          0.17578125    0.17578125
>
> *5) Compute a "Weird" pyramid:*
> In this test, I generate too many levels in the pyramid on purpose :
> cp worldwide_no_pyramid.gpkg worldwide_manual_weird_pyramid.gpkg
> gdaladdo worldwide_manual_weird_pyramid.gpkg 2 4 8
>
> The GPKG tile matrix is exactly the same as in
> worldwide_default_pyramid.gpkg :
> sqlite3 -header -column worldwide_manual_weird_pyramid.gpkg  "SELECT
> rowid,* FROM gpkg_tile_matrix  ;"
> rowid  table_name            zoom_level  matrix_width  matrix_height
>  tile_width  tile_height  pixel_x_size  pixel_y_size
> -----  --------------------  ----------  ------------  -------------
>  ----------  -----------  ------------  ------------
> 1      worldwide_no_pyramid  1           2             1              256
>         256          0.703125      0.703125
> 2      worldwide_no_pyramid  2           4             2              256
>         256          0.3515625     0.3515625
> 3      worldwide_no_pyramid  3           8             4              256
>         256          0.17578125    0.17578125
> 4      worldwide_no_pyramid  0           1             1              256
>         256          1.40625       1.40625
>
> *6) Conclusion *
> The default power-of-two factor list is computed in gdaladdo.cpp. At this
> point, the algorithm is not aware of some GPKG limitations.
>
> I found two workarounds :
>
>    - specify explicitly all zoom levels
>    - add minsize option. The minimum size has to be twice the tile_height
>    / tile_width : -minsize 512
>
> Shouldn't we have a specific check for GPKG while computing the pyramid ?
> For example by deriving the virtual method BuildOverviews() for GPKG ?
>
> Philippe
>
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