[GRASS-user] how to find peaks

[Michael Barton]

Very clever! Thanks much!

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu







On Nov 18, 2009, at 4:09 PM, Daniel Victoria wrote:

> Some friends and I had a similar problem once. We had to find hilltops
> because, according to brazilian environmental legislation, they are
> environmental preserves. (Top 1/3 of the mountain / hill has to be
> preserved)
>
> The way it was done to solve this was to define watersheds on an
> __inverted__ DEM
>
> Basically, once we invert the DEM, the sinks will be your peak. The
> watershed area will be your mountain / hill "influence zone". The
> highest and lowest elevation inside each watershed, are the hill top
> and bottom elevation. The preserved area in each mountain was
> everything above the 2/3 limit (top - (top-bottom)/3).
>
> There were some other things we considered, like maximum slope but,
> the basic idea was to just invert the DEM and work with watersheds...
>
> Cheers
> Daniel
> PS - The entire procedure was done in another commercial GIS software
> but I'm sure it can easily be done in Grass
>
>
> On Wed, Nov 18, 2009 at 8:33 PM, Markus Neteler <neteler at osgeo.org>  
> wrote:
>> On Wed, Nov 18, 2009 at 10:22 PM, Michael Barton <michael.barton at asu.edu 
>> > wrote:
>>> Beyond r.param.scale, is there a good method anyone knows of to  
>>> find peaks
>>> or hilltops? I'm more interested in the tops of hills/high points  
>>> than the
>>> single cell that is the highest.
>>
>> Perhaps r.prominence:
>> http://grass.osgeo.org/wiki/GRASS_AddOns#r.prominence
>> could be of interest?
>>
>> Markus
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