On 04/05/15 11:28, joanna mardas wrote:
Hello,
I'm totally new user of GRASS and of course I have some problems. I want
to do the pre-processing of Landsat (5TM) images (for further band
composite, classification and NDVI) and I was using the tips from
http://grasswiki.osgeo.org/wiki/LANDSAT#Pre-Processing I did the
*i.landsat.toar* I wanted to do the i.atcorr as well but I have no idea
how to do this, the manual was not helpful for me, so I gave up. I did
not do i.topo.corr because the land I'm working on is flat.
And I really want to do "/radiometrically normalise → one approach
via*i.histo.match* (in grass 7), also known as relative radiometric
normalisation -- one approach is the histogram matching technique of two
or more raster maps/". I have fragments of original landsat images
imported to GRASS and i.histo.match works with them without any
problems. But there is a problem when I want to do this on images which
I got after i.landsat.toar. The output images are monochromatic-one
colour. I've used command i.histo.match
input=_toar2@konfa,86_toar2@konfa (the input files are those which I got
after i.landsat.toar) and then r.colors map=86_toar2.match@konfa
color=grey. I thought that those steps from grasswiki should be done
"step by step", so first i.landsat.toar, and then on the output files
i.histo.match.
Does anyone know how to do this in a proper/correct way?
ISTR that i.histo.match works with integer imagerie, i.e. recoded to
0-255. Recode your toar images to that range with r.recode and try to
run the result through i.histo.match to see if that helps.
Moritz
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