[GRASSLIST:136] r.statistics/r.mapcalc returns nan values

[Martin Rutzinger]

hi list!

i use r.statistics to calculate the stddev for areas in my base layer (input is
cover layer). r.statistics returns an output raster containing ids as cat value
and the stddev for each area as lables.

r.statistics base=areas_rast cover=input_rast method=stddev output=stddev_area

if i try to convert the lables to cat all "areas" are empty (="nan" values).

r.mapcalc "final_rast=@stddev_area"

my cover map contains some regions with null values but they are not covered by
an area of the base layer. if i zoom in so that there are no null values within
my region. it works fine.

i tried to reclass the null values in the cover map to 0 - but this did not
help.

had anybody similar problems with r.statistics/r.mapcalc - any suggestions?
thanks for discussing and helping
martin