[GRASS5] g.pnmcomp and Gamma correction (gis.m slider?)

GRASS GIS GRASS GIS developer
1

Hi,

while generating RGB composites, I came across the
problem that sometimes maps appear as too dark
(also when shading maps).

Glynn, would it be possible to add Gamma correction
to g.pnmcomp and, if so,

Michael, to have that as slider below transpacency
in gis.m?

Best

Markus

2

Markus Neteler wrote:

while generating RGB composites, I came across the
problem that sometimes maps appear as too dark
(also when shading maps).

Glynn, would it be possible to add Gamma correction
to g.pnmcomp and, if so,

Possible: yes. Sensible: no.

If needed, gamma correction should be applied before the maps are
rendered, by modifying either the colour table or the cell values
(probably the former).

Maybe r.colors needs a gamma= option?

--
Glynn Clements <glynn@gclements.plus.com>

3

On Thu, Mar 16, 2006 at 03:02:56PM +0000, Glynn Clements wrote:

Markus Neteler wrote:

> while generating RGB composites, I came across the
> problem that sometimes maps appear as too dark
> (also when shading maps).
>
> Glynn, would it be possible to add Gamma correction
> to g.pnmcomp and, if so,

Possible: yes. Sensible: no.

If needed, gamma correction should be applied before the maps are
rendered, by modifying either the colour table or the cell values
(probably the former).

Maybe r.colors needs a gamma= option?

Yes, that sounds reasonable (as well as r.composite).

Markus