[GRASSLIST:4852] Re: Imagery support

[Markus Neteler]

On Mon, Oct 28, 2002 at 03:45:18PM -0500, John A. Preston wrote:
> Hi, Can anybody tell me if there are any tools in GRASS 5.0 to
> brighten a raster image. I have imported a 1m IKONOS image
> (via TIFF) to three bands then using r.composite to a single
> raster file That I will use as a backdrop for display other
> GIS elements. However the composite is rather dark and
> I want to know if there is any possibility in GRASS
> to brighten it.
> 
> I could export the composite raster to TIFF and then use
> an image editor then re-import it but is there another way.

Hi John,

I think you should not change values of the IKONOS image, but you
can adjust the color table (color to value assignment).

Try
 - r.colors with option grey
 - r.colors with option grey.eq
 - r.colors with option rules, then define your own ranges

Usually this will be sufficient.

Markus