Hi Martin, Thanks, that is a exactly the problem. Your page is perfect for showing the cause and solution.
One question though, since the solution relies on removing polygons whose areas are less than a minimum threshold, how can we do this accurately with a global data set? I suppose I could extract each country, reproject it to a local projection, clean out the bad polygons, then reproject to lat/lon, and finally patch all of the separate countries back into single file. Roger -- On Sat, Oct 17, 2009 at 12:57 AM, Martin Landa <[email protected]> wrote: > Hi, > > 2009/10/17 Roger André <[email protected]>: >> Tried the v.extract route - it didn't help. The little segments came > > sure, because there are no 'lines' - just 'boundaries' and 'centroids' > which constract 'areas'. > >> along. So I decided to look at the original data and pull one the >> polygons from it, to see if I could spot anything strange about it. I >> did find something, maybe, maybe one of the experts here can explain >> it. >> >> Here is what v.clean reports: >> >> Number of nodes: 55 >> Number of primitives: 59 >> Number of points: 0 >> Number of lines: 0 >> Number of boundaries: 46 >> Number of centroids: 13 >> Number of areas: 13 >> Number of isles: 9 >> >> This country should have 9 areas, which matches the number of isles. >> I'm trying to figure out how to remove the extra areas (rmarea thresh >> value is tricky), but I wonder if there is a way to make the areas >> match the isles? > > I was facing probably to the similar problem, it's described here [1]. > Sorry it's in Czech, anyway from the commands you can probably > understand what was the problem. I hope it can help you a bit. > > Martin > > [1] > http://gama.fsv.cvut.cz/wiki/index.php/GRASS_GIS_-_Konzistence_vektorov%C3%BDch_dat > > -- > Martin Landa <landa.martin gmail.com> * http://gama.fsv.cvut.cz/~landa > _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
