[GRASS-user] Varying results - v.select,v.distance,v.what

Kevin Webb kfw4 at cornell.edu
Thu Dec 18 14:04:19 EST 2008


At 12:44 PM 12/18/2008, Markus Neteler wrote:
>On Mon, Dec 15, 2008 at 9:07 PM, Kevin Webb <kfw4 at cornell.edu> wrote:
> > At 03:03 PM 11/20/2008, Kevin Webb wrote:
> >
> > Note: I used the phrase "relationship with'" instead of "dependency". OGR
> > will certainly
> > compile without GEOS, but OGR operations without GEOS may yield suspect
> > results.
>
>Isn't it then an OGR problem rather than a GRASS problem?
>We use the OGR and expect that OGR always delivers the same
>result (or issues a warning/error if not possible in absence of GEOS).

If the assumptions and the requirements of the OGR API are as you
have stated here, then this is an issue with OGR and not Grass.


> >
> > Thinking that GEOS may have an impact on Grass, I executed similar
> > before-and-after-GEOS
> > tests in Grass and observed the same improvement; points that resulted in
> > multiple FIDs
> > coming from v.select before-GEOS, yielded a single value after-GEOS.
> > v.select and v.distance
> > return the same value now that GEOS has been installed.
>
>May I ask you to bring this up on the gdal mailing list?
>
>Markus

I am willing to bring this up on the gdal mailing list. Can anyone else
support my observation from their own testing (a simple 'yea' or 'nea' will 
suffice)?


KFW





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