[GRASS-user] Snapping lines to one fix layer

Sonja Jankowfsky sonja.jankowfsky at cemagref.fr
Fri Jan 29 05:27:54 EST 2010


I've got one detailed land-use map and one calculated sub-basin map, 
which I want to intersect in order to create hydrological response units 
(they will also be intersected with geology and soil maps at a later step).

The intersection will give me all sorts of polygons and a lot of small 
polygons.  I suppose, that my land-use map, which was digitized manually 
is correct, and I don't want to loose this information. Contrary, the 
sub-basin map, which was calculated automatically can be changed.

So, I'm looking for a tool to snap the sub-basin borders to the land-use 
borders. If I use v.clean rmarea, this will union the small polygons, 
but change my land-use borders. I tried also to run v.clean snap several 
times, but this will still change the land-use limits.

Is there any tool in GRASS where I can say to which layer I want to snap 
another layer of polygons or lines?

Many thanks,


I can eliminate them with v.clean, rmarea or snap.
Sonja Jankowfsky
UR Hydrologie-Hydraulique
Cemagref de Lyon
3 bis quai Chauveau CP 220
69336 Lyon Cedex 09
Tel : (+33)4 72 20 86 11 	 
Fax : (+33)4 78 47 78 75 

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