[GRASS-user] exported raster seems to be different from source

mrigotti at agrsci.unibo.it mrigotti at agrsci.unibo.it
Fri Oct 13 09:53:42 EDT 2006


I produced a raster map, using grass63-cvs,at a 5m resolution. Cell values were
floating. Then I exported it using r.out.ascii (setting dp=4), and imported it
on another machine, where grass61-cvs is installed, using r.in.ascii.

I run r.univar, and the output was quite different. Here they are:

1st result, from grass63-cvs
total null and non-null cells: 1002834
total null cells: 659566

Of the non-null cells:
n: 343268
minimum: 0
maximum: 21.363
range: 21.363
mean: 0.121939
standard deviation: 0.446553
variance: 0.19941
variation coefficient: 366.209 %
sum: 41857.8619999509

2nd result, from grass61-cvs
total null and non-null cells: 994875
total null cells: 650910

Of the non-null cells:
n: 343965
minimum: 0
maximum: 21.3627
range: 21.3627
mean: 0.121839
standard deviation: 0.44615
variance: 0.19905
variation coefficient: 366.181 %
sum: 41908.3203069364

I understand there might be a difference because of the dp value, which was
different for the two rasters, but I can't understand why the number of cells
is different, when the raster should be the same.
Is it a bug, or just my poor knowledge of GIS systems? Can anyone help?

Thank you very much in advance,
Marco Rigotti

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