[GRASS-user] calculate percentage of land use in larger cells

Moritz Lennert mlennert at club.worldonline.be
Tue Nov 26 02:47:39 PST 2013


Hi,

I'm pretty sure that this has been discussed before and even that some 
solution already exists, but I just can't seem to find the right search 
terms to put my hands on it:

I have a raster layer with landcover at 0:00:10 resolution. I would like 
for a select of the landcover classes raster layers at 0:10 resolution 
with the percentage of surface of the respective class in the new pixel.

Currently I'm thinking of the following possible work flow:

- at resolution of landover map, for each class:
     - r.mapcalc classX = if(cover=X,1,0)

- at coarser resolution
     - r.resamp.stats in=classX out=classX_total method=sum
     - r.mapcalc "classX_perc = classX_total / perc"

As an option one could also replace r.resamp.stats with 
r.out.xyz/r.in.out.xyz, but I'm not sure that there would be any 
advantage to that.

My question is: is there some option in an existing module (or addon 
module) that already does something like this ?

Moritz



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