danotchki wrote:
Hello List,
I hope you will be able to help me. I'm stuck on a problem.
I'm trying to reconstruct within my Python script polygons from a
shapefile that belong together.
So I naturally perfomed:
geom_tmp = ogr.CreateGeometryFromWkb(ftr.GetGeometryRef().ExportToWkb())
geom.AddGeometryDirectly(geom_tmp)
However this works only when the geometry to add is of type POLYGON.
This _doesn't_ work with type MULTIPOLYGON (exit code 3).
Daniel,
What type is "geom"? If it is a MULTIPOLYGON then it can only
have polygons as children, not multipolygons.
My question: is there a way to add MULTIPOLYGONs to an existing Geometry?
What I don't understand is that when CreateGeometryFromWkb returns a
MULTIPOLYGON it actually returns a GEOMETRY instead of a
GEOMETRYCOLLECTION, thus preventing looping on each individual geometry
with GetNumGeometries. Would there be a way to cast the polygon to a
multipolygon?
In C/C++ there are methods on OGRGeometryFactory like
forceToPolygon and forceToMultiPolygon that might be helpful
but I see these are not exposed in Python. Are you willing to
build from SVN trunk source code? If so, I could add these methods
for you.
Best regards,
--
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I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com
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and watch the world go round - Rush | Geospatial Programmer for Rent
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