[postgis-users] (no subject)

dblasby at openplans.org dblasby at openplans.org
Mon Jul 18 10:35:51 PDT 2005


>This sounds like floating point comparisons failing because
>> of numerical
>> rounding issues.
>
>Highly unlikely - JTS/GEOS is very robust wrt predicates.

I think he means the 2 geometries arent actually identical - the points
maybe "10-7 off".  These differences would be hidden by converting to
WKT (since it doesnt show all 64bits of precision).

Try something like this:

SELECT encode( asBinary(  geometry1 ) , 'hex'),
       encode( asBinary(  geometry2 ) , 'hex')
FROM ... ;

And see if the two are actually equal.

dave





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