[GRASS-user] r.what and d.what.rast

Dylan Beaudette dylan.beaudette at gmail.com
Wed Oct 4 13:01:28 EDT 2006


please keep in mind that interactive querying of the display *may* involve 
resampling (via nearest neighbor) when display size is much smaller than the 
actual size. Please see previous posts by Glynn about automatic resampling 
associated with the display architecture- especially since the incorrect 
values are coming from d.what.rast.



On Wednesday 04 October 2006 00:39, Javier Álvarez Rodríguez wrote:
> Thanks a lot for your answer Trevor. I'm not a good programmer but i tried
> to do something more. I exported the map (2300x2900 rowsxcols) to an ascii
> file and tried to read there the correct solution. It seems that the
> correct one is that given by r.what. Maybe that this is a silly question
> but,... Do "d.what.rast" depend on monitor resolution?. I mean the map was
> 2300x2900 cells and don't know how it manages to select coordinates and
> then obtain the value.
> Best regards
> On Mon, 2 Oct 2006 18:13:16 +0200
> Javier Álvarez Rodríguez wrote:
> > Hi all,
> > My problem is about I'm obtaining different results when using
> > d.what.rast and r.what.
> > Using interactively d.what.rast on a map named bas, I obtain these
> > results:
> >
> > 361421.875(E) 4540953.125(N)
> > bas in DATOS, quant   (854)
> > bas in DATOS, actual  (854.000000)
> >
> > Then I write x and y coordinates in a file named pp3.txt
> >
> > 361421 4540953 (no matter real or integer coordinates)
> >
> > and when using r.what
> > r.what bas at DATOS < pp3.txt
> > result is 860
> I'm not sure of the cause, but in doing some tests of the same data
> set, it would appear that r.what is probably reporting incorrectly.
> I looked at the code briefly and can't see any obvious errors, but I'm
> ccing the developers list to see if anyone has seen this bug before.
> T

Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis

More information about the grass-user mailing list