Kris Nackaerts <knackaerts@gmx.net> schrieb am 13.01.04 22:09:11:
I had the same problem when trying to visualize hyperspectral images. I
created a script in R (www.r-project.org) to analyze the histogram
output files and create a GRASS script automatically to correctly
rescale the values for visualisation. I could then say like remove the
5% tails.
I just wrote a small shell script myself which basically uses r.stats, awk and r.colors. Now everything is looking fine!
If you are interested in this script, let me know. Otherwise, I also
used just a PCA transform to get a first impression of what was in the
images.
For the visualization of multispectral data it normally is sufficient to choose some interesting bands by their wavelength, but I agree with you that PCA is a good preprocessing step for visual inspection of a large number of bands.
Wolfgang
______________________________________________________________________________
Erdbeben im Iran: Zehntausende Kinder brauchen Hilfe. UNICEF hilft den
Kindern - helfen Sie mit! https://www.unicef.de/spe/spe_03.php
Kris,
I would like to have your script; thanks.
Tom
Wolfgang von Hansen wrote:
Kris Nackaerts <knackaerts@gmx.net> schrieb am 13.01.04 22:09:11:
I had the same problem when trying to visualize hyperspectral images. I created a script in R (www.r-project.org) to analyze the histogram output files and create a GRASS script automatically to correctly rescale the values for visualisation. I could then say like remove the 5% tails.
I just wrote a small shell script myself which basically uses r.stats, awk and r.colors. Now everything is looking fine!
If you are interested in this script, let me know. Otherwise, I also used just a PCA transform to get a first impression of what was in the images.
For the visualization of multispectral data it normally is sufficient to choose some interesting bands by their wavelength, but I agree with you that PCA is a good preprocessing step for visual inspection of a large number of bands.
Wolfgang
______________________________________________________________________________
Erdbeben im Iran: Zehntausende Kinder brauchen Hilfe. UNICEF hilft den
Kindern - helfen Sie mit! https://www.unicef.de/spe/spe_03.php
--
Thomas E Adams
National Weather Service
Ohio River Forecast Center
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Wilmington, OH 45177
EMAIL: thomas.adams@noaa.gov
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FAX: 937-383-0033