i.cca - GRASS manual
Author: GRASS Development Team
Description: i.cca: Canonical components analysis (CCA) program for image processing.
Keywords: imagery, statistics, CCA, canonical components analysis

## NAME

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

## KEYWORDS

imagery, statistics, CCA, canonical components analysis

## SYNOPSIS

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

### Flags:

--overwrite
  Allow output files to overwrite existing files
--help
  Print usage summary
--verbose
  Verbose module output
--quiet
  Quiet module output
--ui
  Force launching GUI dialog

### Parameters:

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

## DESCRIPTION

i.cca is an image processing program that takes any number of (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.

### Parameters:

group=name
  Name of the imagery group to which the raster band files used belong.
subgroup=name
  Name of the imagery subgroup to which the raster band files used belong.
signature=name
  Name of an ASCII file containing spectral signatures.
output=name
  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.

## NOTES

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

## REFERENCES

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

## SEE ALSO

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

## AUTHORS

David Satnik, GIS Laboratory, Central Washington University
Ali R. Vali, University of Texas
Semantic label support: Maris Nartiss, University of Latvia

## SOURCE CODE

Available at: i.cca source code (history)

Latest change: Friday Aug 08 09:39:19 2025 in commit: ed72c71d8580e872cd6fd345c84a15c324764465

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© 2003-2026 GRASS Development Team, GRASS 8.5.1dev Reference Manual