On Tue, Jan 13, 2015 at 8:41 PM, Markus Metz <markus.metz.gisw...@gmail.com> wrote: > On Sat, Jan 10, 2015 at 7:34 PM, Fábio Dias <fabio.d...@gmail.com> wrote: >> What would be the 'recommended' way of dealing with the 'errors' made >> when the data is created with zero topological restrictions (and saved >> as .shp?) > > For import, try to find a snapping threshold for v.in.ogr that > produces an error-free output. Ideally the output would not only be > error-free, but the number of centroids would match the number of > input polygons (both are reported by v.in.ogr). The min_area option of > v.in.ogr could also help. The bulk of the cleaning should be done by > v.in.ogr. After that, removing small areas with v.clean tool=rmarea, > threshold in square meters, could help. For Terraclass (and PRODES) > which are mainly based on Landsat data, a threshold of 10 square > meters could remove artefacts and preserve valid areas (Landsat pixel > size is about 90 square meters). The threshold needs to be empirically > determined. > > I am not aware of a standard procedure that works for all data sources.
I have taken liberty to merge this answer into http://grasswiki.osgeo.org/wiki/Vector_topology_cleaning markusN _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
