[GRASSLIST:2109] landsat processing

[Ian Macmillan]

Hi all, I have a question about landsat processing.  i am trying to produce a
nice 15m resolution "true color image" from landsat 7 data. I am using band 3
(red) band [2+4]/2 (green) and band 1 (blue).  These three bands produce a very
nice 30m res image with d.rgb.  I would like to incorporate the 15m res band 8
though.  I am going about this by using i.rgb.his and i.his.rgb as described in
the book.  I get an image that is 15m res, however the colors become a little
distorted, namely, the urban areas become purple (instead of grey) and the
vegetated areas become an ugly bright green.  I have tried using both an
histogram optimized band 8 (r.rescale) and the original band 8.

Anybody have any experience with this?  I am really interested in eventually
getting images that look like those produced by NASA here:

http://photojournal.jpl.nasa.gov/catalog/PIA03372

My next step will be to add shading using shade.rel.sh, or some modification of
r.slope.aspect.  Any input would be helpful as I can't figure out how to keep
the colors looking realistic.

Many thanks.

-ian