[GRASSLIST:1834] border lines

[Dieter Lehmann]

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: Thu, 11-May-01 12:00:00 +0000 (GMT)
Time: 16:03:23

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