Ok, thanks. The other three corners were rounded, but I eliminated the rounding with the -s option.
Hanlie 2011/4/20, Markus Metz <markus.metz.gisw...@googlemail.com>: > On Wed, Apr 20, 2011 at 2:21 PM, Hanlie Pretorius > <hanlie.pretor...@gmail.com> wrote: >> Hi, >> >> I'm working in GRASS 6.4.0 and using v.buffer applied to an extents >> rectangle. For some reason v.buffer is producing one chamfered corner >> in the buffered vector. >> > The bug concerning the southwest corner is already fixed in 6.5, > awaiting ok for backport to 6.4.2. > > The 3 other corners are also incorrect, I guess they should be > rounded. At least they are with other areas of similar shape. > > Markus M > > >> The command I used was: >> v.buffer -s -c --overwrite input=c83a_extents@PERMANENT >> output=c83a_extents_5km_buffer@20m_DEM distance=5000. >> Buffering lines... >> Buffering areas... >> Building topology for vector map <c83a_extents_5km_buffer>... >> Registering primitives... >> 1 primitives registered >> 12 vertices registered >> Number of nodes: 1 >> Number of primitives: 1 >> Number of points: 0 >> Number of lines: 0 >> Number of boundaries: 1 >> Number of centroids: 0 >> Number of areas: - >> Number of isles: - >> Snapping boundaries... >> Breaking boundaries... >> Removing duplicates... >> Attaching islands... >> Building topology for vector map <c83a_extents_5km_buffer>... >> Building areas... >> 1 areas built >> 1 isles built >> Attaching islands... >> Number of nodes: 1 >> Number of primitives: 1 >> Number of points: 0 >> Number of lines: 0 >> Number of boundaries: 1 >> Number of centroids: 0 >> Number of areas: 1 >> Number of isles: 1 >> Number of areas without centroid: 1 >> Attaching centroids... >> Building topology for vector map <c83a_extents_5km_buffer>... >> Attaching centroids... >> Number of nodes: 2 >> Number of primitives: 2 >> Number of points: 0 >> Number of lines: 0 >> Number of boundaries: 1 >> Number of centroids: 1 >> Number of areas: 1 >> Number of isles: 1 >> Building topology for vector map <c83a_extents_5km_buffer>... >> Registering primitives... >> 2 primitives registered >> 13 vertices registered >> Building areas... >> 1 areas built >> 1 isles built >> Attaching islands... >> Attaching centroids... >> Number of nodes: 2 >> Number of primitives: 2 >> Number of points: 0 >> Number of lines: 0 >> Number of boundaries: 1 >> Number of centroids: 1 >> Number of areas: 1 >> Number of isles: 1 >> (Wed Apr 20 14:08:46 2011) Command finished (1 sec) >> >> I have placed a screenshot of the outcome on the web >> <http://www.nedbib.za.net/v.buffer.png>. The region was set to the DEM >> raster in the background. The black triangle is the extents and the >> red one the buffered polygon. >> >> Does someone know why v.buffer would create such a chamfered corner. >> I've played around with selecting different feature types and adding a >> minor distance value, but I always get the same result. >> >> Thanks >> Hanlie >> _______________________________________________ >> grass-user mailing list >> grass-user@lists.osgeo.org >> http://lists.osgeo.org/mailman/listinfo/grass-user >> > _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
