[GRASSLIST:1686] m.clump/r.statistics/ and more

[Rado Bonk]

Hi GRASSusers,

I found m.clump command in the "Manuals" section of GRASS web page. But I
did not find it in my compiled GRASS5beta8 on IRIX, neither I did in
GRASS5beta11 binaries for Linux. Is it a part of GRASS4.3 version?

I wonder if there is a way to use GRASS to divide values of slope angle,
or some other attributes, into statistically acceptable and separable
ranges or scales. Something like what clustering algorithm do for you in
ERDAS/Imagine. It is always a problem when one have to categorize
morphometric property into the certain classes and one does't want to use
empiricial tresholds.

PROBLEMS WITH r.statistics:
As for r.statistics, is there any limitations on number of region for base
map? My base map has around 8000 unigue regions, and r.statistics doesn't
work well. For 5-7% of all regions it produces the desired statistics in
hexadecimal format (I think it is hexadecimal). When I run:
r.mapcalc=outputmap_cats=@outputmap

r.mapcalc dies on "Segmentation fault" on IRIX6.5 machines. Original base
map was produced by r.clump, and I ran r.support before I used it for
r.statistics.

r.statistics doesn't work if method=average. I assume it uses some
procedures from r.stats, and there is a bug, at least on IRIX6.5. If
method=min or method=max, it just work for first region in base map(lowest
categoy value, concerns Linux, and IRIX6.5). Again, the base map has 8000
unique regions.

Thanks in advance,

Rado

Rado Bonk
Geography and Geology
UNO, Omaha, NE 68182-0199
rado at cosmos.unomaha.edu
http://rbonk.host.sk