[GRASS-dev] r.slope.aspect: one pixel less in the output at the border shrinks region extent in further calculations

[Helmut Kudrnovsky]

Helmut Kudrnovsky wrote
> hi devs,
> 
> I've added a script [1] with following calculations ideas:
> 
> - do some calculations with r.slope.aspect output
> - coarse the resolution (but meet the DEM extent)
> - do some calculations with r.slope.aspect output at the coarser
> resolution
> - coarse the resolution again  (but meet the DEM extent)
> - do some calculations with r.slope.aspect output at the again coarser
> resolution
> - combine all the results for some index calculation
> 
> as the extent of the r.slope.aspect output is 1 pixel less then DEM input,
> the extent of the calculation output shrinks from one step to the next as
> the resolution is coarsening.
> 
> any idea how to overcome such a shrinking?
> 
> [1]
> http://trac.osgeo.org/grass/browser/grass-addons/grass7/raster/r.valley.bottom/r.valley.bottom.py

for illustrating a screenshot (resolution coarsening: 30x30 -> 90x90 ->
270x270)

<http://osgeo-org.1560.x6.nabble.com/file/n5179919/test.png> 

in the screenshot: original extent of the input DEM and extent of the script
output.

any ideas?



-----
best regards
Helmut
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