On Wed, 2011-07-27 at 14:42 -0700, Rich Shepard wrote: > I have a map of drainage basins and another of the project property > boundary. Of the 4200+ basins in the map, the property is in only a dozen or > so. I'm trying to overlay these maps to produce a union that has only those > basins that drain the property. v.overlay with operator=or yields a combined
Use "AND" not "OR". OR=Union, that is combining all features of both vectors AND=Intersection, that is, just areas or lines covered by both vectors > map of _all_ basins and the property[1] so either I'm not correctly applying > the module, or the resulting map needs more processing with a different > module. Please point me in the right direction to get the results I want. > > After I have a map containing only those basins overlaid by the property > boundary I want to use v.overlay to clip the stream networks in these same > basins. I assume that v.overlay with op=and will do this nicely. My question > is then what process will allow me to extract each drainage basin with its > stream network and portion of the property for terrain and hydrological > analyses and modeling. > > I have another issue with the DEM, but that will be on a separate thread. > > Rich > > [1] Using the wxPython GUI with v.overlay I did not see a data entry widget > to select the operator. It apparently defaults to 'or' but if there's a > radiobox to select 'or,' 'and,' 'not,' or 'xor' I did not see it. > _______________________________________________ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user > > This mail was received via Mail-SeCure System. > >
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