[GRASS-user] calculate pixel areas with starspan

[maning sambale]

commands goes like tihis

#extract number of pixels by class, vector is a municipality shapefile
raster is grass raster
 starspan --vector /home/maning/data/ciPhimuni/ciphimuni.shp --raster
/home/maning/data/manilageog/sealevel3/cellhd/rise_5_reclass --fields
MUNICIPALI --count-by-class /home/maning/data/stat/rise_5_class.csv
--noColRow --noXY --progress

#get statistics
starspan --vector /home/maning/data/ciPhimuni/ciphimuni.shp --raster
/home/maning/data/manilageog/sealevel3/cellhd/rise_5_reclass --fields
MUNICIPALI --stats /home/maning/data/stat/rise_5_stats.csv avg mode
stdev min max --noColRow --noXY --progress

How do I compute class areas for each polygon?

Cheers,

Maning

On 11/21/06, Dylan Beaudette <dylan.beaudette at gmail.com> wrote:
> On Sunday 19 November 2006 21:53, maning sambale wrote:
> > Hi,
> >
> > I have grass rasters and I want to calculate raster classes based on
> > the attributes of a shapefile.  I'm experimenting with starspan and so
> > far its extremely fast than:
> >
> > v.in.ogr #to export shapefile
> > v.build and v.digit #to check for topology problems
> > v.to.rast
> > r.report
> >
> > But, how can I get area coverage (in percent and hectares) from a
> > given raster class in a polygon?
> >
> > Any ideas?
> >
> > Cheers,
> >
> > Maning
>
> Hi Manning,
>
> How are you invoking starspan, and what exactly do you mean by "an area
> coverage" ?
>
> You might check out the "mini-raster" options in starspan:
> --mini_rasters <prefix>
> --mini_raster_strip <filename>
>
> I believe that these will extract "mini" rasters for each vector feature. Be
> sure to read the documentation however.
>
> Cheers,
>
>
> --
> Dylan Beaudette
> Soils and Biogeochemistry Graduate Group
> University of California at Davis
> 530.754.7341
>


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