[GRASS-user] Converting slopes from huge DEM into vector (area)

[Rainer M. Krug]

Hi

I have a huge raster, representing the slopes of a huge DEM (Rows: 
   25960, Columns: 23211, Total Cells:  602557560, Type CELL).
I would like to use R.to.vect to convert it to a vector layer of type 
area. Due to memory requirements, it does not work in one step.

I thought of splitting the raster into several smaller rasters (let's 
say into 100 smaller rasters of the same resolution) for which I could 
use r.to.vect to create the vector layers and in a final step patch the 
vector layers together again.

Before going into the details: is this a feasible approach (I can't 
reduce the resolution as the resolution is needed) or is there another 
solution?

But I am stuck in the first step:
how can I split one large raster layer into several smaller?

and:
What is the easiest way to write the script to do the calculations for 
all 100 raster layers? (I haven't used the scripting in GRASS 6.2.1 yet, 
but I have done a bit scripting under the bash shell)

Any help is welcome,

Rainer

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Rainer M. Krug, Dipl. Phys. (Germany), MSc Conservation
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Leslie Hill Institute for Plant Conservation
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