[GRASS-user] grass-user Digest, Vol 96, Issue 17

Patrick S. patrick_GIS at gmx.ch
Wed Apr 16 23:43:41 PDT 2014

Thanks, Vaclav.

Will keep geomorphons in mind, but run 64 currently. I have pretty much 
the same experience here- almost no peaks. I thought that minor 
differences in the elevation might be the reason and rescaled. Also 
tested change in size but this did not have effects- rather less than 
more peaks, with rising size. But not a single area that covers "peak 
zones", as shown in the manual. I ended up to do the following:

r.neighbors in=elev out=elev.max meth=maximum size=9 --o
r.mapcalc << EOF
     elev.peak = if(elev.max==elev, 1, null())

This works pretty good and I have control on whats happening. Would be 
good to understand what r.param.scale does define as peak, though.


On 04/16/2014 09:00 PM, grass-user-request at lists.osgeo.org wrote:
> Hi,
> r.param.scale should be the same in all the versions (and also manual pages
> are all the same). I don't know r.param.scale much but whenever I'm using
> it I getting almost no peaks. It looks similar to what is in the manual
> page -- almost everything on hills is ridge, just time to time there is a
> peak. Did you try playing with resolution (g.region res=)? If you are not
> satisfied with r.param.scale, in addons for GRASS 7 there is r.geomorphons,
> the results are usually very good if you play with parameters and
> resolution.
> Vaclav
> http://grass.osgeo.org/grass64/manuals/r.param.scale.html
> http://grass.osgeo.org/grass65/manuals/r.param.scale.html
> http://grass.osgeo.org/grass70/manuals/r.param.scale.html
> http://grass.osgeo.org/grass71/manuals/r.param.scale.html
> http://grass.osgeo.org/grass70/manuals/addons/r.geomorphon.html

More information about the grass-user mailing list