[GRASS-user] Help - Tabulate Areas (ESRI function) for GRASS

[Micha Silver]

On 05/30/2012 11:07 PM, Alejandro Coca Castro wrote:
>
> Hi, i have a raster file about land usage  (crops / urban areas ecc..)
>
> I have defined some zones around some given points of a vector layer 
> and I'd like to calculate the % of those areas occupied by each value 
> of the raster file in order to make an estimate on the average usages 
> of the selected areas.
>
> I know that in arcgis there is a function to do so called "Tabulate 
> Areas", but I can't find such feature in GRASS.
>

I think you can use r.stats for this. First rasterize your (vector) 
areas with v.to.rast. Use a numeric column for the "use=attr" option. 
Then use r.stats with both the landuse raster and the zones raster as input.
So if you have a "landuse" raster, and a "zones" vector with i.e. a 
"zone_id" column, then:

v.to.rast in=zones out=zones use=attr colu=zone_id
r.stats -p in=zones,landuse fs=, out=landuse_zones_percent.csv

> If anyone can help me I'd be so grateful.
>
> Regards,
>
>
>
> -- 
> */Alejandro Coca Castro/**//**//**//*//
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