2013/2/26 Markus Metz <[email protected]>: > BTW, v.transform simply transforms coordinates, it does not do any > cleaning. v.transform should actually work without topology, building > topology on the output is optional (in GRASS 7). > [...] > For this particular problem (georectifying overlapping polygons) there > is probably an easier solution outside GRASS. Maybe QGIS supports > coordinate transformation/rectification using GCPs?
Looks like you're right. I will try a newer version of GDAL / OGR. I will also update GRASS, to use "v.rectify", so I can check the values of the transformation matrix, and explore the possibility of working without topology. In QGIS, I could not find an equivalent function. Maybe it exist, but I have looked very little. I know there is a plugin for GCP based transformations, but it is for rasters. Anyway, some of the above alternatives will surely solve my problem. 2013/2/26 Moritz Lennert <[email protected]>: > -1 > > I'm strongly opposed to that option. As you mention, this would > fundamentally undermine the data logic in GRASS. > > To answer José's issue: If you want to keep on working in GRASS, you should > not try to do so with overlapping polygones. Thanks Moritz, I hope fully understand all implications of this topic someday! For now, I promise to not propose something like that anymore. > If all you want to do in GRASS is v.transform, you should be able to import > with cleaning. Wherever there is overlap, you will get new polygones which > have all the category numbers of the original polygones. You can then > v.transform the file and if you need to get the original polygones you > should be able reconstruct them based on the common category numbers. I considered doing this at first. But when I checked the maps imported, I could not find all the information necessary to perform the task. I will follow your instructions if only as an exercise to learn a little more. Thank you very much! Jose _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
