[postgis-users] Difference between @ and ST_WITHIN/ST_CONTAINS

[Dylan Beaudette]

On Tuesday 22 April 2008, Paul Ramsey wrote:
> The operators (@, &&, etc) all work on bounding boxes. The functions
> all work on full geometries. It is possible for geometries to satisfy
> bounding box containment while not satisfying full geometric
> containment, hence your discrepancy.
>
> P.

Thanks for the clarification.

Does it make sense any more to use one of the &&, @, etc. operators to 
pre-filter geometries, or do the ST_ functions take care of that in call 
cases? i.e. can you think of any cases where it would still be a good idea to 
use something like

select st_intersection(a,b)
from a, b
on a && b ;

Thanks,

Dylan

> On Tue, Apr 22, 2008 at 8:36 AM, Frank Durstewitz
>
> <frank.durstewitz at emporis.com> wrote:
> > Hi,
> >  can someone please explain, what the difference between
> >
> >  WHERE ST_CONTAINS(b.geom, e.geom)
> >
> >  and
> >
> >  WHERE e.geom @ b.geom
> >
> >  is? (b.geom are (multi-)polygons and e.geom are points)
> >
> >  I expect to get the same results, but with @ i get a few more
> > records...?
> >
> >  TIA, Frank
> >
> >
> >
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-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341