[GRASSLIST:1835] Re: border lines

Andrea Aime aaime at comune.modena.it
Fri May 11 10:31:27 EDT 2001


Hmmm... sorry, but I can't help you... I guess I should add an option
to r.poly in order to make it output border lines, not area features...
I hope to have enough time this weekend, that's not difficult to do...
but then you have to wait at least until Monday, and then get sources
from CVS and recompile. Now I'm leaving for weekend, I'll be back
on Monday
Regards
Andrea Aime

Dieter Lehmann wrote:
> 
> Hi,
> thanks Andrea, sometimes the simplest solution is the best...
> 
> Another question:
> 
> I don't find a way to extract only the borderlines from rasterized polygons.
> I need this borders in a new raster map (for expample the borders between two
> different soil types).
> 
> I found the script r.edge.dig. It's not exact what I need because this
> extract only between two given categories and not between all
> values in a given raster map.
> 
> Another attemp was to use r.poly, but I don't find the way to make lines from
> the areas (the other way round there is a script available). After that I would
> use v.to.rast
> 
> Thanks a lot.
> Dieter
> 
> On 11-May-01 Andrea Aime wrote:
> > Grass raster approach is to store on category for each
> > raster map: if you want two attributes you'll use two raster
> > maps. If they refer to the same phenomena, you may use a
> > map name convention, such as a common prefix:
> >
> > r.mapcalc test = if(raster_a1 == 1 and raster_a2 == 3, 1, 0)
> >
> > Hope this helps
> > Andrea Aime
> >
> > Dieter Lehmann wrote:
> >>
> >> Hi,
> >> is it possible to refer to different
> >> categorie-values in a single raster-map? (maybe stored in
> >> a database with the database-interface) I want to do a
> >> mapcalc expression somehow like:
> >>
> >> r.mapcalc test = 'if(raster==1 and raster$tabelinfo2 == 3,1,0)'
> >>
> >> Thanks,
> >> Dieter
> >>
> >> ----------------------------------
> >> Dieter Lehmann
> >> University of applied Sciences
> >> Schelmenwasen 4-8
> >> D-72622 Nuertingen, Germany
> >> lehmann at fh-nuertingen.de
> >> Phone: +49 (0) 7022 404 Ext. 207
> >> Fax: +49 (0) 7022 404 Ext. 209
> >>
> >> Date: 11-May-01
> >> Time: 13:57:20
> >>
> >> ----------------------------------
> 
> ----------------------------------
> Dieter Lehmann
> University of applied Sciences
> Schelmenwasen 4-8
> D-72622 Nuertingen, Germany
> lehmann at fh-nuertingen.de
> Phone: +49 (0) 7022 404 Ext. 207
> Fax: +49 (0) 7022 404 Ext. 209
> 
> Date: 11-May-01
> Time: 16:03:23
> 
> ----------------------------------




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