[GRASS-user] GRASS63cvs v.rast.stats reports zero for many CATs

[Maciej Sieczka]

Dylan Beaudette wrote:
> On Friday 06 April 2007 13:36, Brandon M. Gabler wrote:
>> Fellow GRASSers -
>>
>> I am using GRASS 6.3 cvs, the Kynge's build, and I have an issue
>> using v.rast.stats on a raster of slope. Many (n>100) of my
>> archaeological sites, which are all polygons, produced 9 columns of
>> zeros for the slope stat calculations.

Can you provide a GRASS location containing the data necessary to
reproduce your problem, and the exact v.rats.stats command? Otherwise
it's hard to say what could be the problem.

>> The oddest part is that I successfully calculated elevation stats
>> from a DEM raster using the same v.rast.stats command. The slope
>> raster was produced directly from the DEM, so resolution, etc. are
>> exactly the same.

Is it possible that the slope raster has really small values at these
locations, ie. with numbers after 10th decimal place? There is a note
in the v.rast.stats (it's a shell script), line 165:

#check if DBF driver used, in this case cut to 10 chars col names:

Propably Markus (script author) can explain why this is necessary.

Maciek