[R-sig-Geo] [STATSGRASS] v.stats.rast for category raster or vector cross statistics

[Matthew Perry]

Agustin,


I would suggest taking a look at starspan
(http://starspan.casil.ucdavis.edu/). It specializes in
vector-on-raster analyses and has a --count-by-class flag for
categorical rasters. I wrote a bit more about it at
http://www.perrygeo.net/wordpress/?p=30 .

- matt
 On 10/22/07, Agustin Lobo <Agustin.Lobo at ija.csic.es> wrote:
> Dear lists,
>
> Given Av (vector of polygons) and Br (raster of a categorical variable,
> i.e. a classification or a soil map) I want to calculate
> for each polygon in Av, the surface of each category from Br.
>
> v.stats.rast almost does it, but calculates lumped stats for each
> polygon (i.e, assumes that Br is a continuous variable).
>

> Alternatively, I could have Br as another vector Bv, but don't find
> the way of calculating cross stats as r.stats -a in=Ar,Br would do for
> raster layers.
>
> Converting Av into raster Ar is inconvenient, as the polygons are few
> and small and would have to use a very samll cell size (Br is large)
>
> Any easier way through R?
>
> --
> Dr. Agustin Lobo
> Institut de Ciencies de la Terra "Jaume Almera" (CSIC)
> LLuis Sole Sabaris s/n
> 08028 Barcelona
> Spain
> Tel. 34 934095410
> Fax. 34 934110012
> email: Agustin.Lobo at ija.csic.es
> http://www.ija.csic.es/gt/obster
>
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-- 
Matthew T. Perry
http://www.perrygeo.net

"Never ascribe to malice, that which can be adequately explained by
incompetence."