r.param.scale - plan curvature doesn't work

[guano]

Maps of plan curvature calculated using r.param.scale results in a map with a very very very narrow distribution (histogram attached), therefore we can't see any of the features.

[guano]

histogram of plan curvature

[guano]

map of plan curvature. colortable rainbow, histogram equalised

[neteler]

# Spearfish

g.region rast=elevation.10m -p
r.param.scale elevation.10m out=planc param=planc
r.univar planc
total null and non-null cells: 2654802
total null cells: 0

Of the non-null cells:
----------------------
n: 2654802
minimum: -56.0318
maximum: 63.5533
range: 119.585
mean: 0.000136618
mean of absolute values: 0.0203089
standard deviation: 0.0846529
variance: 0.00716612
variation coefficient: 61963.3 %
sum: 362.6935644354

looks like equally distributed to me. The question is: is the color coding bad or is the result wrong? This could be tested with synthetic curves (see source:grass/trunk/testsuite/raster/rhemisphere.sh​)

Markus

[hamish]

adding skewness and kurtosis to r.univar would help in diagnosing this bug. see ​http://article.gmane.org/gmane.comp.gis.grass.devel/31686/

[helena]

I just tried it out - it is just bad color coding - changing to curvature color table works. This can be either fixed in the code or just suggest in the manual to set the color table to curvature. I think this can be closed.

[neteler]

Replying to helena:

I just tried it out - it is just bad color coding - changing to curvature color table works. This can be either fixed in the code

Curvature color code may be taken from here:

​http://trac.osgeo.org/grass/browser/grass/branches/releasebranch_6_4/raster/r.slope.aspect/main.c#L1177