actually I have to patch a mosaic of aerial photos together.
After rectifying them I want to have one big image
containing all the others.But now I run into trouble because the colors of all pictures
except one (the first I specified in r.patch) are wrong.Does anybody know how to patch images properly?
That should be possible in GRASS!
I don't know if YOUR images are taken from a scanner, but I
had your problem in such a case.
If the images are scanned, it may well happen that you have a
mismatch in the color lookup tables (i.e. the same color corresponds
to different cell values, scanner-gurus please comment).
For this reason you get only the first patched image looking ok,
while all the others go berserk.
if you r.mapcalc "img_new=#img_old" you create e new set of images
in which the correspondence between color codes and cell values
is re-established, and your "patchwork" should get a more
consistent look.
Clearly this procedure is applicable only for visualization purposes.
hope this helps!
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Andrea Giacomelli
Centre for Advanced Studies, Research and
Development in Sardinia
Environment Division
http://www.crs4.it/~andreag
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