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List:       postgis-users
Subject:    Re: [postgis-users] equals and =
From:       Mark Cave-Ayland <mark.cave-ayland () siriusit ! co ! uk>
Date:       2008-04-24 9:42:48
Message-ID: 48105618.3080806 () siriusit ! co ! uk
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Paul Ramsey wrote:
> I'm going to go out on a limb here, without consulting the source
> code, and say that the '=' operator is comparing the representations
> of the geomtries, so only geometries that have exactly the same
> vertices in exactly the same order starting at exactly the same point
> are counted.  The equals() function is allowing for differences in
> start point, direction and inconsequential vertices.
> 
> YMMV.
> 
> P


Hi Rhys/Paul,

I think that the '=' is specified by the B-Tree operator class, in which 
case according to the source, equality appears to be specified simply by 
bounding box equality.


ATB,

Mark.

-- 
Mark Cave-Ayland
Sirius Corporation - The Open Source Experts
http://www.siriusit.co.uk
T: +44 870 608 0063
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