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Hi everybody, <br>
<br>
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:<br>
<br>
1. <b>("alt@1">0 or "alt@1"=<0)*2</b> gets a raster layer
with value 2 per cell (let's put name =value2).<br>
<br>
<div>2. <b>"value2"^"alt@1"</b> 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<br>
<br>
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. <br>
<br>
I tried with grass plugin r.mapcaculator function, but also it
didn't work.<br>
<br>
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).<br>
<br>
the link to the example layer: <br>
<br>
<a class="moz-txt-link-freetext" href="http://biogeo.ucdavis.edu/data/climate/worldclim/1_4/grid/cur/alt_10m_bil.zip">http://biogeo.ucdavis.edu/data/climate/worldclim/1_4/grid/cur/alt_10m_bil.zip</a><br>
<br>
best<br>
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<pre class="moz-signature" cols="72">--
Sergio A. Estay
Inst. Ciencias Ambientales y Evolutivas
Universidad Austral de Chile
Casilla 567, Valdivia, Chile
Phone: 5663-293913
<a class="moz-txt-link-freetext" href="http://www.ciencias.uach.cl/instituto/ciencias_ambientales_evolutivas/academicos/sergio-estay.php">http://www.ciencias.uach.cl/instituto/ciencias_ambientales_evolutivas/academicos/sergio-estay.php</a></pre>
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