[postgis-users] geos result sets

[James S reid]

yeah - was kinda thinking along those lines ; ) interesting that ESRIs
solution is not exact - does tat vary by patform and product I wonder?

james
----- Original Message ----- 
From: "Paul Ramsey" <pramsey at refractions.net>
To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
Sent: Thursday, February 26, 2004 3:52 PM
Subject: Re: [postgis-users] geos result sets


> Intersects() *might* work. However, it might be a bit too broad. What
> you want is "interior of A interacts with interior of B". I do not know
> my Relate() function well enough, but there should be a Relate()
> pattern that gives you what you want. Time to haul out your SFSQL and
> read up on the 9 way dimensionally extended model... :)
> P.
>
> On Thursday, February 26, 2004, at 01:15 AM, James S reid wrote:
>
> > thanks for that - I can see where you are coming from even if the
> > results
> > ends up a little unexpected - interstingly, if you use a distance() = 0
> > function you get the 'correct' result so I guess there is some
> > intrinsic
> > tolerance in the distance() function?
> > one consequence of course is that geometries would need to be very
> > clean to
> > prevent this sort of behaviour. Have you any thoughts on what
> > operators I
> > could use that would give me the expected result without have to check
> > for
> > data inconsistencies ? In practical terms I need to be able to
> > establsih
> > containment without the exacting tolerances that geos seems to demand?
> > Will
> > the distance function work predicatbly on differnt machine
> > architectures?
>
>       Paul Ramsey
>       Refractions Research
>       Email: pramsey at refractions.net
>       Phone: (250) 885-0632
>
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