[Gvsig_english] About NDVI and Map Calculator in Sextante Toolbox
afalciano at yahoo.it
Thu Nov 22 15:09:19 CET 2007
Victor Olaya ha scritto:
> can you send me that small layer you are using? I will try to see what
> happens and tell you a solution or fix the error.
> Thanks for using sextante!
the Quickbird image is too large, so I tried to export to Raster my area
of interest and then I discovered where is the problem: there is an
error when gvSIG reads the DN of every single band to associate to TIF
raster. In detail:
- band 1 (B) is read as band 3,
- band 2 (G) is read as band 1,
- band 3 (R) is not read,
- band 4 (NIR) is read as band 2.
Band 4 of the TIF raster is always equal to zero. It explains why NDVI =
0 everywhere without having any warning/error message!
If I export my image band by band, the DN values are correctly read.
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