GRASS GIS manual: i.spec.unmix

NAME

i.spec.unmix - Performs Spectral mixture analysis of satellite/aerial images

KEYWORDS

imagery, spectral unmixing

SYNOPSIS

i.spec.unmix
i.spec.unmix help
i.spec.unmix group=name matrix=name [result=string] error=name iter=name [--overwrite] [--verbose] [--quiet]

Flags:

--overwrite: Allow output files to overwrite existing files
--verbose: Verbose module output
--quiet: Quiet module output

Parameters:

group=name: Name of input imagery group
matrix=name: Open Matrix file; Matrix file containing spectral signatures
result=string: Name of raster map prefix to hold spectral unmixing results
error=name: Name of raster map to hold unmixing error
iter=name: Name of raster map to hold number of iterations

DESCRIPTION

i.spec.unmix is used to perform Spectral Unmixing.

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)

AUTHOR

Markus Neteler, University of Hannover, 1999

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

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