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The Spatialite-based sqlite dialect of GDAL/OGR as used by QGIS when filtering GPKG or Spatialite layers can not handle some more complex curved geometries. For example MultiSurface(CurvePolygon(CompoundCurve(CircularString(...) as you might find in ALKIS data.
If such geometries exist in a layer to be filtered, they are ignored by the filter.
A possible workaround is linearizing the affected datasets using the "Segmentize by maximum angle" processing tool. An angle of 4° would match what GDAL/OGR's -nlt CONVERT_TO_LINEAR or other linearization of curves seems to use. This is a lossy process though and thus might not be desirable.
The text was updated successfully, but these errors were encountered:
Apparently this affected all kinds of curve geometries so #7 does that.
kannes
changed the title
Complex curve geometries in GPKG/Spatialite are ignored by filtering
Curve geometries in GPKG/Spatialite are ignored by filtering
Feb 7, 2023
Spatialite uses Google Groups as "mailing list" which cannot be used without a Google account. I mailed Alessandro Furieri directly on 2023-07-17 to ask about a estimate of the work required and potential sponsorship.
sandro added on 2023-07-23 13:27:40:
I'm sorry, but I really don't think CIRCULARLINESTRINGS etc will ever be supported by SpatiaLite, at least not in the near future.
it is a demanding modification that would certainly have a very heavy impact on the project, and unfortunately the available resources are decidedly scarce.
If you are reading this and if you might be able to contribute to a significant funding, please contact me.
The Spatialite-based sqlite dialect of GDAL/OGR as used by QGIS when filtering GPKG or Spatialite layers can not handle some more complex curved geometries. For example
MultiSurface(CurvePolygon(CompoundCurve(CircularString(...)
as you might find in ALKIS data.If such geometries exist in a layer to be filtered, they are ignored by the filter.
https://gis.stackexchange.com/questions/446768/working-with-circularstring-in-ogrs-sqlite-dialect has some tests with
ogrinfo
in it.The upstream ticket in Spatialite is https://www.gaia-gis.it/fossil/libspatialite/tktview/cfa630d01b9baf56d663ed991f630de807477f6e
A possible workaround is linearizing the affected datasets using the "Segmentize by maximum angle" processing tool. An angle of 4° would match what GDAL/OGR's
-nlt CONVERT_TO_LINEAR
or other linearization of curves seems to use. This is a lossy process though and thus might not be desirable.The text was updated successfully, but these errors were encountered: