On Wed, Apr 20, 2011 at 4:41 PM, Hanlie Pretorius <[email protected]> wrote: > Ok, thanks. > > The other three corners were rounded, but I eliminated the rounding > with the -s option.
Oops, I missed that -s option. Anyway, v.buffer is not chopping off corners also with the -s option in 6.5. Markus M > > 2011/4/20, Markus Metz <[email protected]>: >> 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
