[GRASS-user] calculating perimeter per patch
Milton Cezar Ribeiro
miltinho.astronauta at gmail.com
Sat Feb 12 05:58:27 EST 2011
Thanks for the reply. In fact a vector-based should solve this.
But, unfortulatelly, as I am working with a very large raster map
(48,000 x 60,000 pixels; 250,000 clumps), and GRASS fail when
I try r.to.vect under Windows/Vista. Is there any other options
of convert large raster maps to vector, instead of r.to.vect?
2011/2/12 Markus Metz <markus.metz.giswork at googlemail.com>
> On Sat, Feb 12, 2011 at 5:11 AM, Milton Cezar Ribeiro
> <miltinho.astronauta at gmail.com> wrote:
> > Dear all,
> > I have a raster map where each patch (i.e. forest fragment) have
> > ID.
> > I need to estimate the perimeter per patch, but R.le.patch can't do the
> Have you tried a vector approach? Then the perimeter can be simply uploaded
> v.to.db option=perimeter.
> (Watch out for the fractal problem, both r.le.patch and v.to.db)
> Markus M
> > ------------
> > GRASS 6.4> r.le.patch map=fragments sam=w per=p1 siz=s1 out=STATS.txt
> > PARAMETER CHOICES:
> > MAP: fragments
> > SAMPLE: whole map TRACING: 8 neighbor
> > SIZE MEASURES:
> > mean patch size
> > PERIMETER MEASURES:
> > sum of perims
> > R.LE.PATCH IS WORKING....;
> > ERROR: G_calloc: unable to allocate 24806 * 8 bytes at alloc_cell.c:83
> > ------------
> > Any hint?
> > bests
> > milton
> > _______________________________________________
> > grass-user mailing list
> > grass-user at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/grass-user
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