[gdal-dev] GPKG footprint of ratser data shrinks as zoom level decreases

[Philippe Ghesquiere]

Dear Jukka,

This is exactly the origin of my "missing pixels". The open option " -oo
USE_TILE_EXTENT=YES" yields the right pyramid

Thanks
Philippe


On Mon, Apr 20, 2026 at 1:42 PM Rahkonen Jukka <
jukka.rahkonen at maanmittauslaitos.fi> wrote:

> Hi,
>
> When it comes to extents at different zoom levels, it is expected that
> they change. Rasters are stored into GeoPackage as tiles and lower zoom
> level tiles cover larger area.
>
>
> https://learn.microsoft.com/en-us/azure/azure-maps/media/zoom-levels-and-tile-grid/quadkey-tile-pyramid.png
>
> The GDAL GPKG driver has some open options which affect how the extents
> are calculated
> https://gdal.org/en/stable/drivers/raster/gpkg.html#opening-options
>
> But the shrinking extent feels like option "USE_TILE_EXTENT=YES" gets used
> while the default should be "USE_TILE_EXTENT=NO". Try if using explicit NO
> helps, or specify the extent with MINX/MINY/MAXX/MAXY. Notice that using
> the extent of the lowest zoom level always may lead into high number of
> empty tiles at higher zoom levels.
>
> -Jukka Rahkonen-
> ________________________________________
> Lähettäjä: gdal-dev <gdal-dev-bounces at lists.osgeo.org> käyttäjän Philippe
> Ghesquiere via gdal-dev <gdal-dev at lists.osgeo.org> puolesta
> Lähetetty: Maanantai 20. huhtikuuta 2026 12.37
> Vastaanottaja: gdal-dev <gdal-dev at lists.osgeo.org>
> Aihe: [gdal-dev] GPKG footprint of ratser data shrinks as zoom level
> decreases
>
> HUOM! Ulkoinen lähettäjä. Älä avaa linkkejä tai liitteitä, ellet tunnista
> lähettäjää. OBS! Extern avsändare. Öppna inte länkar eller bilagor om du
> inte känner igen avsändaren. NOTE! External sender. Do not open links or
> attachments unless you recognize the sender.  Hi all,I have problems with
> the footprint of GPKG raster data, as it varies with zoom level.1) Data
> creationI need a color-relied'ed DTED in GPKG format. I create it with the
> following commands:gdaldem  color-relief  E017N30.DT2 colormap.lut
>  E017N30_lut.tifgdal_translate -of GPKG -co TILING_SCHEME=InspireCRS84Quad
> -co ZOOM_LEVEL_STRATEGY=UPPER -co RASTER_TABLE=tiles -r bilinear
>  E017N30_lut.tif E017N30_lut.gpkggdaladdo E017N30_lut.gpkg2) ObservedUL and
> LR corners are given with (where zoom max is ZOOM_LEVEL=12):gdalinfo.exe
> E017N30_lut.gpkg | grep -E "Upper Left|Lower Right"Upper Left  (
>  16.9998611,  31.0001389) ( 16d59'59.50"E, 31d 0' 0.50"N)Lower Right (
>  18.0001320,  29.9998680) ( 18d 0' 0.48"E, 29d59'59.52"N)I noticed that the
> GPKG footprint depends on zoom level:gdalinfo.exe E017N30.gpkg -oo
> ZOOM_LEVEL=7| grep -E "Upper Left|Lower Right"Upper Left  (  16.9998611,
>  31.0001389) ( 16d59'59.50"E, 31d 0' 0.50"N)Lower Right (  17.9996170,
>  30.0003830) ( 17d59'58.62"E, 30d 0' 1.38"N)We observe:UL corner are
> identicalLR corner "moves" northward and westward from Z=12 to Z=8Is it as
> expected?3) Impact:When computing the pyramid (gdaladdo), one column (on
> the east side) and one line (on the south side) are not generated.In our
> system, we can see this artefact when when requesting tiles with WMTS
> requests.4) WorkaroundOur generation script is currently based on
> gdal_translate/gdaldem/gdaladdo (and not mapcache_seed). In order to get
> all the expected pixels, I implemented a workaround:* generate the highest
> zoom level layer with standard gdadem/gdal_translate commands (see above)*
> sqlite command: increase max_x and decrease min_y in table gpkg_contents*
> gdaladdo: pyramid computation* sqlite command: reset max_x and min_y to
> original valuesThank you for any help / explanationPhilippeThe information
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