[GRASSLIST:2186] How to display satellite data correctly?

[Wolfgang von Hansen]

Hi,

currently I am doing some first steps with GRASS to see how it all works. I've got some sample data (Landsat TM) that I would like to analyze with some of the available functions. However it seems that GRASS is not very good at displaying color images -- at least not if the histograms of the individual channels aren't properly equalized.

There is r.colors that should do the trick (I've tried grey.eq) but the results weren't too good. To my opinion the histogram is transformed to be a little like black-and-white but the dynamics aren't well. The display of d.rgb is extremely bright colored but it is difficult to see the real structure -- there are quite a few colored noise pixels that also degrade the quality.

Are there better ways to display and visually analyze satellite data? What I am especially missing is a simple linear stretch of the histogram with a 1% cutoff at each end.

Wolfgang
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