[GRASS-user] how to find peaks

[Michael Barton]

Thanks or all the suggestions. We will be trying these out. In the  
meantime, I had a few minutes this evening and was messing around with  
r.param.scale. I discovered that the minic option does a pretty good  
job of identifying peaks too (minimum curvature perpendicular to  
direction of maximum curvature). It also does a good job of finding  
valleys. Here are a couple of screenshots of the following settings  
applied to the Spearfish 30m DEM

r.param.scale -c --overwrite input=elevation.dem at PERMANENT  
output=aaa_rparamscaletest size=31 param=minic

http://www.public.asu.edu/~cmbarton/files/temp/peaks.png (only values  
above 0.0002 are shown)
http://www.public.asu.edu/~cmbarton/files/temp/peaks_nviz.jpg (I have  
no idea what is causing the weird linear holes at the top and bottom  
of the output map)

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 2:33 PM, grass-user-request at lists.osgeo.org wrote:

> Date: Wed, 18 Nov 2009 14:22:29 -0700
> From: Michael Barton <michael.barton at asu.edu>
> Subject: [GRASS-user] how to find peaks
> To: grass-user grass-user <grass-user at lists.osgeo.org>, list GRASS
>        developers <grass-dev at lists.osgeo.org>
> Message-ID: <FBAF608E-D86D-4B2C-A631-19C328829D3B at asu.edu>
> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>
> 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.
>
> Thanks
> 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