Hi, Martin With the same configuration (almost, Python 2.6.5 instead of 2.6.1) and with a shapefile "TM_WORLD_BORDERS-0.3" downloaded from http://geocommons.com, I've got no problems invoking the method "intersection" for France with Spain as parameter. Is this the same shapefile you've used ?
Pascal 2011/1/9 Martin Laloux <[email protected]> > Hello, I have a problem with multipolygon intersection > >>> import osgeo.ogr > >>> import shapely.wkt > >>> from shapely.geometry import MultiPolygon > >>> shapefile = osgeo.ogr.Open("TM_WORLD_BORDERS-0.3.shp") > >>> layer = shapefile.GetLayer(0) > >>> espagne = None > >>> france = None > >>> for i in range (layer.GetFeatureCount()): > ... feature = layer.GetFeature(i) > ... if feature.GetField("ISO2") == "FR": > ... geometry = feature.GetGeometryRef() > ... france=shapely.wkt.loads(geometry.ExportToWkt()) > ... if feature.GetField("ISO2") == "ES": > ... geometry = feature.GetGeometryRef() > ... espagne=shapely.wkt.loads(geometry.ExportToWkt()) > > >>> print france.wkt > MULTIPOLYGON (((9.4858320000001299 42.6152730000001156, ... > >>> print espagne.wkt > MULTIPOLYGON (((-17.9127809999999386 27.7716640000000439, ... > >>> france.intersects(espagne) > True > >>> x = france.intersection(espagne) > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > File > "/Library/Python/2.6/site-packages/Shapely-1.2.8-py2.6.egg/shapely/geometry/base.py", > line 331, in intersection > return geom_factory(self.impl['intersection'](self, other)) > File > "/Library/Python/2.6/site-packages/Shapely-1.2.8-py2.6.egg/shapely/topology.py", > line 55, in __call__ > "This operation produced a null geometry. Reason: unknown") > shapely.geos.TopologicalError: This operation produced a null geometry. > Reason: unknown > > I am on Mac OS X 10.6 with 64bits Python 2.6.1 > Is it a problem of the geos library or Shapely ? > Thanks > Martin > > _______________________________________________ > Community mailing list > [email protected] > http://lists.gispython.org/mailman/listinfo/community > >
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