DESCRIPTION

Concept of mixed pixels (Landsat example)

EXAMPLES

g.region rast=lsat7_2002_10 -p

# Find pure endmembers, they are supposed to be in the corners of
# the PCA feature space (or use spectral measurement data)

i.pca -n input="lsat7_2002_10,lsat7_2002_20,lsat7_2002_30,lsat7_2002_40,lsat7_2002_50,lsat7_2002_70" out=pca_lsat7_2002
d.correlate layer1=pca_lsat7_2002.1 layer2=pca_lsat7_2002.2

# TODO: problem: how to obtain the unprojected coordinates for the corner pixels?
# (in 1998 the xgobi software did this nicely, check today's ggobi)


i.group group=lsat7_2002 subgroup=lsat7_2002 \
  input=lsat7_2002_10,lsat7_2002_20,lsat7_2002_30,lsat7_2002_40,lsat7_2002_50,lsat7_2002_70

i.spec.unmix group=lsat7_2002 matrix=sample/spectrum.dat result=lsat7_2002_unmix \
  error=lsat7_2002_unmix_err iter=lsat7_2002_unmix_iterations

# todo: reclass to 0..100%

REFERENCES

• Neteler, M., 1999: Spectral Mixture Analysis von Satellitendaten zur Bestimmung von Bodenbedeckungsgraden im Hinblick auf die Erosionsmodellierung. M.Sc. thesis, University of Hannover, Germany.
• Neteler, M., D. Grasso, I. Michelazzi, L. Miori, S. Merler, and C. Furlanello, 2004. New image processing tools for GRASS. - In Proc. Free/Libre and Open Source Software for Geoinformatics: GIS-GRASS Users Conference, 12-14 Sep 2004, Bangkok, Thailand.
• Neteler, M., D. Grasso, I. Michelazzi, L. Miori, S. Merler, and C. Furlanello, 2005. An integrated toolbox for image registration, fusion and classification. International Journal of Geoinformatics, 1(1), pp. 51-61. (PDF)

SEE ALSO

• i.spec.sam
• http://www.research.att.com/~andreas/xgobi/
• http://www.public.iastate.edu/~dicook/xgobi-book/xgobi.html
• http://lib.stat.cmu.edu/general/XGobi/

AUTHOR

Mohammed Rashad (rashadkm gmail.com) (2012, update to GRASS 6)

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