[cc'd from grass-dev ML] Hi,
a couple of points-- * Radim said many times: v.in.ogr's cleaning and v.clean are not the same thing. (with a number of !! added) He explained it and understood it always better than I ever could, so check in the mailing list archives for details. * GRASS is a topological GIS. so when data is imported into GRASS it is natural and desirable that it gets converted into the family way at that time. * In defense of the option to allow non topological imports: in the past I have imported a shapefile created by leading proprietary non-topological GIS. this file was a string of buffers around points with unique ID numbers. the idea was to run (the predecessor to) v.rast.stats on each buffer to collect some neighborhood context stats for each ID point, which could be loaded into a table. wherever the line of points was not exactly straight the buffers overlapped a little and grass's cleaning would treat it as a ven diagram and create a new centroid in the overlapping sliver. no good for extracting the buffer area where='NODE_ID = 1234'. also you might consider a vector area map with multiple over- lapping home ranges for different territorial animals. not 3d, but still merging/flattening overlapping areas is not appropriate. for things like neighboring land parcels, political lines, or land/sea boundaries non-topological is a nightmare, but for other tasks it can occasionally be very useful. Hamish _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
