Hi Rich,
I'm sure there's a historical reason for this, but it looks like GDAL has
two very similar methods: GetCoordinateDimension() and
CoordinateDimension(). The former, rather surprisingly, returns only 2 or
3. The latter one returns the value you're looking for:
>>> from osgeo import ogr
>>> g = ogr.CreateGeometryFromWkt('POINT ZM (1 2 3 4)')
>>> g.CoordinateDimension()
4
>>> g.GetCoordinateDimension()
3
Dan
On Mon, Jun 29, 2026 at 2:45 PM Richard Greenwood via gdal-dev <
[email protected]> wrote:
> In Python, I want to find the coordinate dimension of my source. For
> example, with a postgis table with geometry(MultiLineStringZM,4326). My
> Python:
>
> in_lyr = in_ds.ExecuteSQL(select)
> feature0 = in_lyr.GetNextFeature()
> feature0_geom = feature0.GetGeometryRef()
> feature0_geom.GetGeometryType() # 3005
> ogr.GeometryTypeToName(3005) # '3D Measured Multi Line String'
> feature0_geom.GetCoordinateDimension() # 3
>
> Based on:
> https://gdal.org/en/stable/api/vector_c_api.html#_CPPv425OGR_G_CoordinateDimension12OGRGeometryH
> I am expecting the coordinate dimension to be 4. Am I approaching this
> incorrectly?
>
> --
> Richard W. Greenwood
> _______________________________________________
> gdal-dev mailing list
> [email protected]
> https://lists.osgeo.org/mailman/listinfo/gdal-dev
>
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