[GRASS-user] Not being able to produce decent-look color-composites

[Daniel Victoria]

what I normally do is first run r.colors -e color=grey on each band so
I get a equalized color composite. Then I run r.composite. So far I've
got good results...

On Mon, Feb 13, 2012 at 8:16 PM, Glynn Clements
<glynn at gclements.plus.com> wrote:
>
> Luisa Peña wrote:
>
>> I'have 3 layers of Landsat (Green, Red and Near-Infrared) and I'm trying to
>> produce a false-color composite (r.composite( with those but... I'm getting
>> very frustrated because I'm producing very bad look composites. My layers
>> are reflectances from 0-1.8 or something. Shall I rescale them to 0-255?
>
> r.composite uses the colour table associated with each map to convert
> the map's value to an intensity.
>
> If 1.8 represents "full intensity", then use e.g.:
>
>        r.colors mapname rules=- <<EOF
>        0.0 black
>        1.8 white
>        EOF
>
> If you want a non-linear relationship, you can either contruct a
> colour table using a piecewise-linear approximation, or apply the
> transformation to the data with r.mapcalc.
>
> --
> Glynn Clements <glynn at gclements.plus.com>
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