[GRASS-user] how to find peaks

[Daniel Victoria]

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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