[GRASS-user] r.le.patch moving window output and other moving window commands

[Koen Hufkens]

Okay,

I got Grass 6.2 running and r.le.setup works fine (my data didn't work
well at first with r.le.setup it seems). But I ran a windowed r.le.patch
analysis (this is why I needed the r.le.setup to work in the first
place) and it didn't produce the expected results.


I have a gradual transition of one type to another but not in values but
rather in patch size and density (classified as 1 and 2 - binary so to
speak). the line below illustrates it more or less.

type 1 --- patchy type 1 and type 2 -- type 2

and an image:

http://users.pandora.be/requested/images/input.jpg

So I was thinking of running a moving window analysis across this image
returning in the first place a mean patch size for every moving window,
you can think of this more or less like a weighted average according to
patch size. I expected a continuous output but this was not the case.

This is the output I get on the input image above:

http://users.pandora.be/requested/images/mean-patch-size.jpg

(in this case I used round windows, if I use square windows I get the
same result with square yellow and green patches)

I noticed that in r.neighbors and r.mfilter results are rounded to the
nearest integer (resulting in non continuous results). Is this also the
case in the results of r.le.patch using the moving window approach (sam
= m). In addition to my r.le.patch problem, is there a way to get real
values out of r.mfilter or r.neighbors or an alternative function? It
seems a little strange to force a rounded output onto people while this
rounding would just be a reclass of a real valued output.

Kind regards,
Koen