Hanlie Pretorius wrote: > > I don't really know why the > resolution in the x and y directions are not the same. Even when I set > them explicitly, I get a slight difference:
The -a flag is missing, see my previous post. > ----- > g.region -p vect=c83a_bor...@permanent nsres=25 ewres=25 > projection: 99 (Transverse Mercator) > zone: 0 > datum: ** unknown (default: WGS84) ** > ellipsoid: wgs84 > north: -3122229.69982072 > south: -3155672.30728643 > west: -66483.27873573 > east: -33474.90929218 > nsres: 24.99447494 > ewres: 25.00634049 > rows: 1338 > cols: 1320 > cells: 1766160 > ----- > > The original resolution of the DEM was at 25m resolution. I just > assumend that the differences in x and y resolutions are a result of > the projected surface being skew with respect to the cartesian axes. I > say this because vectors that looked square in a latlong GCS display > slightly skewed when projected to the Transverse Mercator PCS that I > use in this location. Ah, ok, set the computational region in the target location with Transverse Mercator PCS and align with g.region -a to the desired resolution, then reproject, then run r.watershed and r.to.vect. > > My reason for running r.watershed at a much finer resolution was that > I would get a smoother boundary when I then convert to vector. > Obviously not a good idea. > Someone still has to fix v.generalize for smoothing boundaries... Markus M _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user