---
name: "i.landsat.rgb"
section: "1grass"
platform: "linux"
package: "grass-doc"
version: "6.4.4-1"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/i.landsat.rgb"
---

# i.landsat.rgb(1grass)

Performs auto-balancing of colors for LANDSAT images.

## NAME

**i.landsat.rgb**  - Performs auto-balancing of colors for LANDSAT images.

## KEYWORDS

raster, imagery, colors

## SYNOPSIS

**i.landsat.rgb**\
 **i.landsat.rgb help**\
 **i.landsat.rgb** \[-**fpr**\] **red**=*string* **green**=*string* **blue**=*string*  \[**strength**=*float*\]   \[--**verbose**\]  \[--**quiet**\]

### Flags:

- **-f**

  Extend colors to full range of data on each channel

- **-p**

  Preserve relative colors, adjust brightness only

- **-r**

  Reset to standard color range

- **--verbose**

  Verbose module output

- **--quiet**

  Quiet module output

### Parameters:

- **red**=*string*

  LANDSAT red channel

- **green**=*string*

  LANDSAT green channel

- **blue**=*string*

  LANDSAT blue channel

- **strength**=*float*

  Cropping intensity (upper brightness level)\
   Options: *0-100*\
   Default: *98*

## DESCRIPTION

*i.landsat.rgb* auto-balances and enhances the color channels of a LANDSAT RGB image to provide a more natural color mixture. Only the color table of each image band is modified, the base data remains untouched.

The module works by calculating a histogram for each color channel and  removing an adjustable amount of outliers from either end before recalibrating the color scale with *r.colors*.

It will work with any 8-bit RGB imagery set and the script is easily modified to work with other datasets of greater band-depth.

## NOTES

Depending on the image, it may or may not be advantageous to use the **-p** flag to preserve the relative color scaling. You will have to experiment with the different options to find a setting that works best for your particular imagery.

The **strength** option should generally be set in the 90-99 range. The lower the number, the more saturated the image becomes. It represents the percentage cut-off for the top end of the color histogram curve. The lower end is fixed at 2% of the area under the curve.

For quicker execution of this module on large images you can achieve largely similar results by switching to a coarser resolution before the running of the module (using *g.region*) and then back to the original resolution afterwards.

## EXAMPLE

North Carolina sample dataset example:\
 `g.region rast=lsat7_2002_10 -p`\
 `d.rgb blue=lsat7_2002_10 green=lsat7_2002_20 red=lsat7_2002_30`\
 `d.barscale at=55.312500,93.125000 bcolor=white tcolor=black -t`\
\
 `i.landsat.rgb blue=lsat7_2002_10 green=lsat7_2002_20 red=lsat7_2002_30 strength=95`\
 `d.rgb blue=lsat7_2002_10 green=lsat7_2002_20 red=lsat7_2002_30`\
 `d.barscale at=55.312500,93.125000 bcolor=white tcolor=black -t`\
 Uncorrected RGB composite of Landsat ETM channels B/G/R

Color corrected RGB composite of Landsat ETM channels B/G/R

## TODO

The **strength** option requires further refinement.

## SEE ALSO

*d.rgb*, *g.region*, *i.oif*, *r.colors*, *r.composite*, *r.univar*,

## AUTHORS

Markus Neteler, Trento, Italy\
 M. Hamish Bowman, Dept. Marine Science, Otago University, New Zealand

*Last changed: $Date: 2012-02-13 17:19:58 +0100 (Mon, 13 Feb 2012) $*

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