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@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@lists.osgeo.org wrote:
Date: Wed, 18 Nov 2009 14:22:29 -0700
From: Michael Barton <michael.barton@asu.edu>
Subject: [GRASS-user] how to find peaks
To: grass-user grass-user <grass-user@lists.osgeo.org>, list GRASS
developers <grass-dev@lists.osgeo.org>
Message-ID: <FBAF608E-D86D-4B2C-A631-19C328829D3B@asu.edu>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yesBeyond 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 UniversityPhone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu