Hi Markus, Il 12/02/2018 21:46, Markus Metz ha scritto:
> The original data in EPSG:3003 and EPSG:3857 are not identical. The > original data in EPSG:3003 are topologically correct, while the original > data in EPSG:3857 are not. interesting. so reprojecting creates errors (tiny gaps, in fact). just to document, the process was importing a shapefile into PostGIS, at the same time reprojecting from 3003 to 3857 > Further on, the original data in EPSG:3857 > contain features that are not present in the original data in EPSG:3003 > which is quite strange. forget about this, polygons added after import > Reprojecting the original data in EPSG:3003 to EPSG:3857 within GRASS > works fine, also with subsequent v.generalize. > > That means that the original data in EPSG:3857 are some reprojected > version of the original original data (which are these?). The > reprojection step, apparently performed on polygons, not GRASS areas > (how did you reproject?), introduced topological errors. Please use > native GRASS v.in.ogr + v.proj to reproject polygons. right; an easy alternative when working with QGIS Processing is to add a snap param, which cures the small gaps. All the best, and thanks again. -- Paolo Cavallini - www.faunalia.eu QGIS & PostGIS courses: http://www.faunalia.eu/training.html https://www.google.com/trends/explore?date=all&geo=IT&q=qgis,arcgis _______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user
