[GRASS-user] Questions: Clipping polygon layer to the outer boundary of another layer...

[Hamish]

Rick Reeves wrote:
> I'm using v.in.ogr to clip a polygon set (in this case, county 
> boundaries) to the boundary of a (rectangular) raster image.
> 
> As far as I know, this is the only way to do this; I tried to create
> a new location with the same boundaries and import the polygon
> shapefile into the location, but clipping did not occur as expected.
> 
> In any case, v.in.ogr did not clip the 'boundary polygons' to the the
> edge of the raster image, but included the entire polygon. Only
> excluded polygons completely outside of the bounding box are clipped.

I assume you used 'v.in.ogr spatial='. This works like v.select.

> There MUST be a way to clip all polygons to the bounding box edge.
> Can any one suggest a way?

v.in.region + v.overlay.


> The second edition of Netler's book discusses v.cutregion.sh and 
> v.cutter methods, but I cant find any evidence of these in GRASS 6.2.

See the GRASS 5<->6 module porting list on the wiki:
  http://grass.gdf-hannover.de/wiki/GRASS_Module_Porting_List

and the GRASS 6.3 module synopsis:
  http://grass.ibiblio.org/gdp/grassmanuals/grass63_module_list.pdf


Hamish



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