[postgis-users] geos result sets

[James S reid]

not disjoint() is worse!! in case its my sql heres the query :

test=# select nuts3.* into temp from nuts2,nuts3 where not
disjoint(nuts3.the_geom,nuts2.the_geom) = TRUE and nuts2=2;

essentially Ive two tables and im tryinbg to sd a polygon in polygon
selection - arcview correctly brings back 8 records - the above brings 15!!

my original with within() qurey looked like:

test=# select nuts3.* into temp from nuts2,nuts3 where
within(nuts3.the_geom,nuts2.the_geom) = TRUE and nuts2=2;

this brought 7 polys back - 1 less than AV and I cant figire out my it
dislikes it !! BTW - reversing the tables and using a contains() also brings
back 7 polys so I think its something in the geos computation??

however - my SQL may be naive so if anyone can correct me Id appreciate it
:)

regards

james

----- Original Message ----- 
From: "Paul Ramsey" <pramsey at refractions.net>
To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
Sent: Tuesday, February 24, 2004 3:50 PM
Subject: Re: [postgis-users] geos result sets


> The definition of Within() is not what you think it is.
> Try using "Not Disjoint()".
> P.
>
> On Tuesday, February 24, 2004, at 06:59 AM, James S reid wrote:
>
> > further to my eralier queries, Ive been doing some experimenting - i
> > consistently get less polys that Im convinced i should using the
> > within() operator on 2 tables (mr ESRI agrees with me) - so either the
> > geos computation is wrong, arcview is wrong or theres some subtlety in
> > the precision that im missing.
> >
> > has anyone else noticed weird things going on?
> >
> > Postgis 0.8.0/1 pg 7.4.1 geos 1.0 cywin environment
> >
> >
> > regards
> >
> > james
> > Edinburgh
> > _______________________________________________
> > postgis-users mailing list
> > postgis-users at postgis.refractions.net
> > http://postgis.refractions.net/mailman/listinfo/postgis-users
> >
>       Paul Ramsey
>       Refractions Research
>       Email: pramsey at refractions.net
>       Phone: (250) 885-0632
>
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