Richard wrote: > With closer inspection of the displayed file, there are > clearly 10 delineated areas, certainly not 323. The majority > of centroids seem to sit on boundary lines.
it is probably tiny sliver areas along doubled boundaries which need cleaning up. typically grass maintains just one boundary between two adjoining areas, while some other GIS maintain two full area polygons with a doubling up where they touch. for various reasons those two overlapping boundaries may deviate slightly during processing, and the result is fractional overlap which shows itself when GRASS builds the topology. the help page for v.overlay talks about it, and has some screenshot examples of what you're describing. see also http://trac.osgeo.org/qgis/ticket/3126 no doubt others here will have the magic v.clean or otherwise recipe to clean it up. Hamish _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
