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 <[email protected]>
wrote:
On Wed, Nov 18, 2009 at 10:22 PM, Michael Barton <[email protected]
> 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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