[GRASS-user] divergent color tables

[Hamish]

> Carlos wrote:
> > I was wondering if we could have divergent color tables. Say I
> > have a map of standard deviation, with a very symmetric
> > distribution around zero. Can I have the same colors diverging
> > from zero? so that +5 and -5 have the same color?

Glynn:
> Are you referring to a specific colour table, e.g. similar to
> color=differences but with the same colour at each end, or an option
> to "mirror" any colour table?
> 
> The former is trivial; just use a rules file such as:
> 
> 	0% blue
> 	0 red
> 	100% blue


a few notes:

- see the included GRASS 'aspect' color rules, they are:
0% black
50% white
100% black

- there are lots of GMT compatible color tables that look like that which
can be loaded with new r.cpt2grass script. see:
  http://grass.gdf-hannover.de/wiki/GRASS_and_GMT#Importing_from_GMT 

- there's a bug in r.colors:
  http://article.gmane.org/gmane.comp.gis.grass.devel/22645
  (now gforge bug # 508)


Hamish