[GRASS-user] r.in/out.xyz question

[Frank Broniewski]

Hi List,

I am experimenting with r.in/out.xyz. As far as I understand, r.out.xyz take a 
cell center coordinate and writes this and the associated z value into 
something(stout/file).
Now I have recognised while importing the output with r.in.xyz that there is a 
different cell count with different rasters while the region is the same.

I have a region with 670480 cells (986 x 680). Each test raster (srtm data and 
derived slope from srtm) says the same with r.info.

Now I get different messages from r.in.xyz for the cell count: The correct 
number of cells for the srtm data (670480 ) but another for the slope raster 
(667152). Checking the output files, the number of lines differ: 67048 lines 
for the srtm and 667152 lines for the slope raster.

I am sorting the output by the z value in order to create classes of equal 
area and the import from the slope raster doesn't work as expected, there's a 
large amount of cells associated to the * - value (Null I presume) instead of 
the classes I defined.

From the manual I read that NULL values are not exported by r.out.xyz. Is 
there maybe a problem with 0 (degree) values from slope?

Greetings Frank