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I want to intersect contours with polygon like in the image below. But i got this error:

GEOS geoprocessing error: One or more input features have invalid geometry.
Some output geometries may be missing or invalid.

I dont know, whats wrong with my geometries? I even dont know, where to search for. I testet it also with a simple single-line. Same happend. The result: a empty shapefile

enter image description here

What should i do now? Where can i expeact a invalid geometry? Or is it because of the shapefile (OGR ESRI)? Please help!


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Have you tested the validity of the contours and the polygon layer? (Vector - Geometry tools - Check geometry validity) It should show where the problem is located. – underdark May 25 '12 at 8:35
No errors found! But I do it now with ogr2ogr:… – MAP May 25 '12 at 11:11
up vote 1 down vote accepted

I have encountered the same problem elsewhere. Reset the CRS. Go to Settings>Project Properties> CRS and Set a Reference system again. This should do the job. If not, export it as an ESRI shapefile.

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