Hi everybody,
I am trying to convert a raster layer "alt" into exp(alt) or log(alt).
Using the raster calculator it was impossible. Carlos Cerdán suggested
me this workaround:
1. *("alt@1">0 or "alt@1"=<0)*2* gets a raster layer with value 2 per
cell (let's put name =value2).
2. *"value2"^"alt@1"* must be a layer with each cell elevated to some
value on "alt@1". If value in cell of "alt@1" is big, you get "inf"
(infinite?) values
However, in step 1 I obtained a layer with just NaN values (for example
with the attached layer and many others). Also trying 2^"alt@1" I
obtained just NaN values.
I tried with grass plugin r.mapcaculator function, but also it didn't work.
Any ideas how can I make this operations inside Qgis or Grass? (In the
meantime I proccess my layers in R without problems, raster package).
the link to the example layer:
http://biogeo.ucdavis.edu/data/climate/worldclim/1_4/grid/cur/alt_10m_bil.zip
best
--
Sergio A. Estay
Inst. Ciencias Ambientales y Evolutivas
Universidad Austral de Chile
Casilla 567, Valdivia, Chile
Phone: 5663-293913
http://www.ciencias.uach.cl/instituto/ciencias_ambientales_evolutivas/academicos/sergio-estay.php
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