[GRASS5] Overlay of maps

[Andrea Aime]

v.cutter doesn't work properly, and up to now I know no way of
doing polygon overlay. I'm studying some computational geometry
and some good article in order to implement vector analysis 
in GRASS 5.1, but up to now I didn't found the time to write 
a line of code... sorry
Regards
Andrea Aime

Robert Lagacé wrote:
> 
> We would like to overlay polygons (intersection) to create new maps.  In the
> process to test GRASS for this purpose, we build simple maps of a few polygons
> (less than 5) by hand.  We import them with v.in.ascii and run v.support.
> 
> v.patch build new maps putting together all the polygons but not intersecting
> them.  v.cutter go weird trying with a map of three polygons and another of
> one polygons feeding us with the following message :
> 
> Building intersection table
> Building new polygons   GOT TO WEIRD STUFF
> GOT TO WEIRD STUFF
> . . .
> [snip of lines and lines]
> GOT TO WEIRD STUFF
> 
> We need to stop v.cutter.
> 
> Is there any other ways to overlay polygons in GRASS?
> 
> What need to be done?
> 
> --
> Robert Lagacé, professeur
> Pavillon Comtois
> Université Laval
> Ste-Foy, Québec, G1K 7P4
> tel : (418)-656-2131#2276
> Fax : (418)-656-3723
> E-mail : lagace at grr.ulaval.ca
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