[GRASS-user] Optimal Window Size in r.forestfrag?

Hi all,

I’m using r.forestfrag to find forest patches in Texas (entire state) but am struggling to figure out a good methodology for determining the optimal window size. The default is 3x3 but I need to be able to make an objective determination vs. just going with the default setting.

Does anyone know of any resources for determining the optimal window size for the forestfrag analysis?

https://grass.osgeo.org/grass70/manuals/addons/r.forestfrag.html

Thank you very much,
Robert Ross Wardrup

Hi Robert,

On Tue, Sep 20, 2016 at 6:00 PM, Ross Wardrup <minorsecond@gmail.com> wrote:

I'm using r.forestfrag to find forest patches in Texas (entire state) but
am struggling to figure out a good methodology for determining the optimal
window size. The default is 3x3 but I need to be able to make an objective
determination vs. just going with the default setting.

3x3 is the default because that's often acceptable size for size of a
moving window in GIS/RS. But don't rely on it. The example shows 7 and 11.
Try different ones and see if the result actually fits with how you would
describe patch, edge, etc. in your landscape. Note, that you may need to
use different window sizes and combine the result in some way.

Does anyone know of any resources for determining the optimal window size
for the forestfrag analysis?

I suggest the original article linked from the manual page. They use
different window sizes and get different results.

http://www.ecologyandsociety.org/vol4/iss2/art3/

Best,
Vaclav