[GRASS5] [bug #1442] (grass) NVIZ Whiteout

Request Tracker grass-bugs at intevation.de
Tue Nov 26 09:01:08 EST 2002


this bug's URL: http://intevation.de/rt/webrt?serial_num=1442
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Subject: NVIZ Whiteout

Platform: GNU/Linux/i386
grass obtained from: Trento Italy site
grass binary for platform: Compiled from Sources
GRASS Version: 5.0.0

I have a georeferenced Aster-DEM and Spot-Data in a LL-Location.
Displaying each of them individually within NVIZ works fine.
Alas, draping the Spot imagery over the DEM fails in a strange way:

The Spot-datas color table was set to WAVE to ensure a bright and colorful
result, while DEM was set to a rather dull GREY.EQ table.

Applying the Spot data as "color" for the DEM renders a purely white
landscape.

The mentioned spot scene is definetely not a sibirian 'winter wonderland' or
a frozen lake, there should be quite a bit of data appearing on screen.

Both data sets are well behaved: r.info  shows ranges of 73-250 (DEM) and
1-14 (Spot), no NULLs.
I already probed for a possible scaling problem:
The DEMs resolution is 0:00:00.9 while the Spot imagery is about 0:00:00.3
Setting the g.region to the lower of the two values didn't affect the
white-out phenomena at all.

Any help/advice would be much appreciated
Peter

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