'False' color composition

[Henrique Barbosa]

Dear Christophe,

You can create any RGB colour with grads command:

set rgb color# R G B

where color# is the color number and must be between 16 and 99,
and R,G,B are integer values between 0 and 255. However, the
way grads works, you have to define clevs and ccols to be used.
I mean, you have to do something like:

set rgb 21 255 100 0
set rgb 22 100 255 10
set rgb 23 50 200 50
set ccol 21 22 23
set clevs 40 50

so that it will use color 21, for values below 40, color 22, for values
between 40 and 50 and so on.... You see? You cannot use the
value of the field at a grid box to specify its color. You have to
give grads a range of values and a color to associate with
that range.

Maybe you can do what you want with a GIS software like GRASS.

Cheers,
Henrique

On 9/26/07, Ricardo Marcelo <ricardom at acd.ufrj.br> wrote:
> 100? it is not 256? maybe should be good to take a look at rgb.gs script to
> get more information.
>
>
> On 9/26/07, Davide Sacchetti <davide.sacchetti at arpal.org> wrote:
> > sorry, grads handles 100 colors only ...
> > I'm afraid you have no chances to do it with grads (at least with
> > version 1.9)
> >
> > Bye bye
> > Davide
> >
> > On Tue, 2007-09-25 at 16:06 +0200, Christophe LAVAYSSE wrote:
> > > Dear all,
> > > I would like to create a 'false' color composition from satellite data
> where
> > > R - G and B colors intensities (O to 255) are defined by the intensity
> of
> > > three different variables (IRchannel1 - IRchannel2 and IRchannel3).
> > >
> > > Does anyone can help me ?
> > >
> > > Thx in advance
> > >
> > --
> > Sacchetti Davide
> > ARPAL UO3 Centro Meteo Idrologico Regione Liguria - Dir. Scientifica
> > V.le Brigare Partigiane 2 16121 Genova (I)
> > tel: +39 010 6437535
> > mail: davide.sacchetti at arpal.org   web: www.meteoliguria.it
> >
>
>
>
>  --
> ============================================================
> Ricardo Marcelo da Silva
> LAMMA - Laboratório de Modelagem de Processos Marinhos e Atmosféricos
> Depto de Meteorologia - Instituto de Geociências
> Centro de Ciências Matemáticas e da Natureza
> Universidade Federal do Rio de Janeiro
> e-mail: ricardom at acd.ufrj.br
> phone: 55 21 2598-9470 r 24
> ============================================================