<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 TRANSITIONAL//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8">
<META NAME="GENERATOR" CONTENT="GtkHTML/3.28.3">
</HEAD>
<BODY>
On Wed, 2011-07-27 at 14:42 -0700, Rich Shepard wrote:
<BLOCKQUOTE TYPE=CITE>
<PRE>
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
</PRE>
</BLOCKQUOTE>
<BR>
Use "AND" not "OR". <BR>
OR=Union, that is combining all features of both vectors<BR>
AND=Intersection, that is, just areas or lines covered by both vectors<BR>
<BR>
<BLOCKQUOTE TYPE=CITE>
<PRE>
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
<A HREF="mailto:grass-user@lists.osgeo.org">grass-user@lists.osgeo.org</A>
<A HREF="http://lists.osgeo.org/mailman/listinfo/grass-user">http://lists.osgeo.org/mailman/listinfo/grass-user</A>
This mail was received via Mail-SeCure System.
</PRE>
</BLOCKQUOTE>
<BR>
</BODY>
</HTML>