[GRASSLIST:2261] Re: r.patch -- problem solved

Malcolm Williamson malcolm at cast.uark.edu
Fri Aug 3 14:58:03 EDT 2001

Check out the man page for r.colors; it describes how color ramps are defined.
If you actually look at your color table (under $LOCATION/colr), you'll see how
it works. Most of the colortables (excluding "rules" and "random", I think)
defined in r.colors are written as ramps, meaning that there are not specific
colors written in the colr file. Try zooming in to part of your DEM, so that you
can see individual cells, and compare nlev=32 to nlev=256. I believe you'll see
a difference, using d.what.rast to identify cell values associated with
different colors. I just tested this, so I know it to be true.

Hope that helps,
	-Malcolm Williamson
	 CAST - University of Arkansas

Rich Shepard wrote:
> On Fri, 3 Aug 2001, Malcolm Williamson wrote:
> > If  you're using the default settings for your graphics monitor, you're only
> > getting 32 color levels each for R, G, and B (a total of 32,768 colors). Try
> > bumping the "nlev" argument up d.mon up to 64, 128, or even 256 levels.
>   That works -- as far as GRASS reporting more colors available when I
> restart the monitor. I'm not seeing a greater gradation in the displayed DEM
> map. I can specify a background color with the d.rast command, but not a
> range of colors.
>   r.colors has pre-defined color tables. It appears that 'wave' has the
> greatest range of colors. Is this a valid assumption?
> Thanks,
> Rich
> Dr. Richard B. Shepard, President
>                        Applied Ecosystem Services, Inc. (TM)
>             2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
>  + 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshepard at appl-ecosys.com
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