i.cca(1grass)

💖 i.cca — the manual page, but make it make sense 💖

okay bestie, welcome to i.cca(1grass), straight out of the GRASS User's Manual ✨ this is the glow-up version of the page, same facts, way more fun. no cap.

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✨ NAME ✨

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

🏷️ KEYWORDS 🏷️

imagery, statistics, CCA, canonical components analysis

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🌸 SYNOPSIS 🌸

so here's how you actually call it, bestie:

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

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🎀 Flags 🎀

• --overwrite — lets your output files go ahead and overwrite files that already exist 👑 (yes, it will actually do it, so be mindful)
• --help — prints the usage summary, iykyk 🙈
• --verbose — verbose module output, so it tells you everything it's doing 💅
• --quiet — quiet module output, for when you want it to just do the thing in silence 🤫
• --ui — forces the GUI dialog to launch 🖥️✨

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🫶 Parameters 🫶

• group=name [required] — name of the input imagery group
• subgroup=name [required] — name of the input imagery subgroup
• signature=name [required] — file containing spectral signatures ✍️
• output=name [required] — output raster map prefix name

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💅 DESCRIPTION 💅

so i.cca is an image processing program that takes any number of (raster) band files plus a signature file, and then outputs the same number of raster band files — except transformed so the categories indicated by the signatures are maximally separable 🔥. this implementation of the canonical components transformation is based on the algorithm contained in the LAS image processing system. also, fun fact: CCA is also known as the "Canonical components transformation" 👑

typically you'd 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 get specified on the command line by giving the group and subgroup that were used to collect the signatures 🧚

and the output raster map names? they're built by appending a ".1", ".2", etc. onto the output raster map name you gave on the command line ✨

🍓 Parameters (the deep dive) 🍓

• 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. 🎀

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📝 NOTES 📝

i.cca respects the current geographic region definition and the current mask setting while performing the transformation 🫶 (yes, both. it's respectful like that.)

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📚 REFERENCES 📚

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

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👀 SEE ALSO 👀

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

the whole friend group, honestly 💜

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👑 AUTHORS 👑

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

icons, all of them ✨

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🌈 SOURCE CODE 🌈

Available at: i.cca source code (history)

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

Main index | Imagery index | Topics index | Keywords index | Graphical index | Full index

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periodt. that's the whole page, bestie 💀💖

and finally, the cute little sign-off: this whole thing lives under © 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual 🎀 and yeah, the manual is stamped GRASS 8.5.0 and it's the i.cca(1grass) page, so you know exactly where you are 🌸🦋