[GRASS-user] calculating perimeter per patch

[Milton Cezar Ribeiro]

Hi Markus,

I will try that. The GRASS_VECTOR_LOWMEM=1 works only for G7?

best

milton

2011/2/12 Markus Metz <markus.metz.giswork at googlemail.com>

> On Sat, Feb 12, 2011 at 11:58 AM, Milton Cezar Ribeiro
> <miltinho.astronauta at gmail.com> wrote:
> > Hi Markus,
> >
> > 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?
> >
> No, but you could try a recent version of GRASS 7 and after starting
> GRASS, set at the commandline
>
> export GRASS_VECTOR_LOWMEM=1
>
> then try r.to.vect
>
> It will take some time, but it should finish eventually.
>
> Markus M
>
> >
> > Markus Metz:
> >>
> >> Milton Cezar Ribeiro:
> >> > Dear all,
> >> >
> >> > I have a raster map where each patch (i.e. forest fragment) have
> >> > different
> >> > ID.
> >> > I need to estimate the perimeter per patch, but R.le.patch can't do
> the
> >> > job.
> >>
> >> Have you tried a vector approach? Then the perimeter can be simply
> >> uploaded with
> >> 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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