[GRASSLIST:9208] Re: Color shaded relief

[Jason Horn]

Micheal,

Thanks for the tips.  I have found that exaggerating the z factor has  
helped somewhat.  What i'm most interested in is how you got your  
results to look so saturated and bright.  I find that when combining  
the dem map (hue) with the shade map (intensity) using d.his, I end  
up with very muddy results because every color is darkened by some  
level of grey from the greyscale shade map.  I'd love to see the  
original shademap you used and the color table that got you those  
results.  I'm impressed.

- Jason




On Nov 23, 2005, at 2:09 AM, Michael Barton wrote:

> A couple things to keep in mind. As Ian MacMillan, you can exercise  
> a lot of
> control over the color table of the draping map.
>
> Also, there are several ways to control the creation of the shaded  
> relief
> map. Besides changing the altitude of the sun (lower makes more  
> shadows and
> accentuates relief), you can also change the z-exaggeration of the  
> relief.
> It is set by default to 1, but I often change it to 2 (double the  
> apparent
> relief).
>
> Attached is a small jpeg example of what you can do.
>
> Michael
>
>
> __________________________________________
> Michael Barton, Professor of Anthropology
> School of Human Evolution and Social Change
> Arizona State University
> Tempe, AZ 85287-2402
>
> phone: 480-965-6213
> fax: 480-965-7671
> www: http://www.public.asu.edu/~cmbarton
>
>
>
>> From: Jason Horn <jhorn at bu.edu>
>> Date: Tue, 22 Nov 2005 16:59:58 -0500
>> To: GRASS Users List <GRASSLIST at baylor.edu>
>> Subject: [GRASSLIST:9189] Color shaded relief
>>
>> 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
>
> <polop_cam_studyarea1.jpg>