Monitor colors

[martijn at scanner.frw.uva.nl]

One other reason for Grass images to contain less greyscale values than 
they should is that they really do. That is, you either never had 256 
different values in the image or you lost them during import/conversion 
procedures. The first thing to do is to query your Grass image using 
"r.cats" to find out if there really are only 31 values left. If this 
proves true, and you're POSITIVE that the original image contained more 
different values than that, you must have lost them somewhere. This means 
you have to check every step along the way. Hopefully you will discover 
that you inadvertently resampled the image - the `save at original size' 
checkbox in Xv comes to mind as a plausible cause.

P. Martijn van Leusen
Institute of Prehistory, University of Amsterdam   martijn at scanner.frw.uva.nl