i.cca.1grass man page

i.cca — Canonical components analysis (CCA) program for image processing.


imagery, statistics, CCA, canonical components analysis


i.cca --help
i.cca group=name subgroup=name signature=name output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]


Allow output files to overwrite existing files
Print usage summary
Verbose module output
Quiet module output
Force launching GUI dialog


group=name [required]
Name of input imagery group
subgroup=name [required]
Name of input imagery subgroup
signature=name [required]
File containing spectral signatures
output=name [required]
Output raster map prefix name


i.cca is an image processing program that takes from two to eight (raster) band files and a signature file, and outputs the same number of raster band files transformed to provide maximum separability of the categories indicated by the signatures. This implementation of the canonical components transformation is based on the algorithm contained in the LAS image processing system. CCA is also known as "Canonical components transformation".

Typically the user will use the g.gui.iclass program to collect a set of signatures and then pass those signatures along with the raster band files to i.cca. The raster band file names are specified on the command line by giving the group and subgroup that were used to collect the signatures.

The output raster map names are built by appending a ".1", ".2", etc. to the output raster map name specified on the command line.


Name of the imagery group to which the 2 to 8 raster band files used belong.
Name of the imagery subgroup to which the 2 to 8 raster band files used belong.
Name of an ASCII file containing spectral signatures.
Output raster map prefix name. The output raster map layer names are built by appending a ".1", ".2", etc. onto the output name specified by the user.


i.cca respects the current geographic region definition and the current mask setting while performing the transformation.

See Also

g.gui.iclass, i.pca, r.covar, r.mapcalc


Schowengerdt, Robert A. Techniques for Image Processing and Classification in Remote Sensing, Academic Press, 1983.


David Satnik, GIS Laboratory, Central Washington University
Ali R. Vali, University of Texas

Last changed: $Date: 2014-12-03 09:40:27 +0100 (Wed, 03 Dec 2014) $

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