I want to intersect contours with polygon like in the image below. But i got this error:
Warnings: 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
What should i do now? Where can i expeact a invalid geometry? Or is it because of the shapefile (OGR ESRI)? Please help!