Thank for your suggestions but I think adding building polygon points just gives more wrong splitting of buildings. The building below should only have been split in 3 pieces:
<http://osgeo-org.1560.n6.nabble.com/file/n5034406/Split_Building.png> And I do not have any data to do a dissolve even if it visually is clear what polygons to join. Extra points should be so far away from the address points that the dividing line between the extra points and address points are outside the building polygon. That is why I have suggested to add some far away points on the edge of (or perhaps rather somewhere outside) the Analysis Extent. Regarding Victors comment on Sextante and the awareness of selections in input layers I can tell that I am using Qgis 1.8 with the latest update of the Sextante plugin (1.0.9) and it treats selections in input data for the Qgis Voronoi Polygons (fTools?) quite strange (I have selected the 5 yellow points and just run the Voronoi Polygon): <http://osgeo-org.1560.n6.nabble.com/file/n5034406/Strange_Voronoi.png> ----- Regards Morten Qgis 1.8.0 Stand alone installer in Win7 64 bit -- View this message in context: http://osgeo-org.1560.n6.nabble.com/Any-ideas-Splitting-polygons-to-only-have-one-point-in-each-polygon-tp5034081p5034406.html Sent from the Quantum GIS - User mailing list archive at Nabble.com. _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user