[GRASSLIST:9190] Re: Color shaded relief

Ian MacMillan ian_macmillan at umail.ucsb.edu
Tue Nov 22 17:19:03 EST 2005


Jason, the method I generally use is similar to yours with some slight 
changes.  I am pretty happy with my results, but each person has their 
own tastes naturally.

Using r.shaded.relief, set your altitude to a higher angle, I typically 
use 60.
Your color map is important.  I use the following color map for maps 
with topography and bathymetry.
8200		255		255		255
7000		255		252		225
5000		252		245		193
4000		252		237		147
3250		250		231		105
2000		177		157		72
230		70		120		50
0		0		82		30
-1		255		255		255
-511		211		227		237
-915		152		218		235
-1519		127		255		255
-2165		204		255		255
-2722		224		251		255
-4200		33		163		255
-5800		38		57		224
-6500		148		33		255
-10799		0		0		0

You can set this (or another color scheme) to your map by first copying 
and pasting this table into a file (make sure to preserve UNIX carriage 
returns).  Then use
cat your_file | r.colors color=rules map=DEM

then use d.his h_map=DEM i_map=DEM.shade

g'luck
-Ian

On Nov 22, 2005, at 1:59 PM, Jason Horn wrote:

> Hi all,
>
> I'm wondering if anyone out there has had experience creating
> attractive color shaded relief images from DEMs.  The basic procedure I
> have used is as follows:
>
> 1) r.shaded.relief DEM azimuth=270 altitude=30
> 2) d.his h_map=DEM_shadei_map=DEM
>
> This is the procedure suggested in Markus' book.  My problem is that
> I always end up with rather muddy-looking results.  I have tried all
> kinds of variations on this procedure, including different altitude
> settings, recoloring the hillshade with a contrast-enhancing
> greyscale color scheme before running r.his, etc.  No real
> improvement.  As an example of what I'm shooting for, have a look at
> this:
>
> http://www.srh.noaa.gov/ridge/grk.shtml
>
> Can anyone suggest a technique for achieving this quality?
>
>
> - Jason
>
>
> Jason Horn
> Boston University Department of Biology
> 5 Cumington Street  Boston, MA 02215
>
> jhorn at bu.edu
> office: 617 353 6987
> cell: 401 588 2766
>
>
 >
 >
What happens if a big asteroid hits Earth? Judging from realistic 
simulations involving a sledge hammer and a common laboratory frog, we 
can assume it will be pretty bad.
  - Dave Barry


-------------------------------------------------------------
This message has been scanned by Postini anti-virus software.




More information about the grass-user mailing list