On Wed, Apr 20, 2011 at 2:21 PM, Hanlie Pretorius <[email protected]> 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 > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
