[GRASS-dev] Re: [GRASS-user] circle surrounding neighbors

[Michael Barton]

Thanks very much Glynn. We're using r.neighbors as part of a complex surface
process modeling routine. This may help to solve a recent set of weird
results we've been getting.

Michael


On 7/31/07 1:54 AM, "Glynn Clements" <glynn at gclements.plus.com> wrote:

> 
> Glynn Clements wrote:
> 
>>> Sorry, I am a beginner... what shall I do with this gather-circle.c?
>> 
>> Replace raster/r.neighbors/gather.c with the new file, re-compile,
>> install the modified r.neighbors as e.g. r.neighbors.circle.
>> 
>> If you don't have the source code or can't figure out how to make the
>> necessary changes, you'll need to wait until someone integrates it
>> into GRASS.
> 
> FWIW, I've added a -c flag to r.neighbors to use a circular
> neighborhood rather than a square.
> 
> I'm unsure as to whether the test should be < or <=. It's currently
> <=, but that gives "spikes" (single cells) at the four edges. Using <
> would give "flats", and would always omit the outermost row/column of
> pixels. Maybe there should be a +0.5 in the distance calculation?

__________________________________________
Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton