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Re: [geos-devel] Re: ST_Contains doesn't work?
by tjordan
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Just to clarify, the problem occurs when the first geometry in an ST_Contains operation is not a rectangle and the second parameter is a rectangle.
SELECT
ST_Contains(
GeomFromText('POLYGON((0 0,0 10,10 10,10 0,0 0))', -1),
GeomFromText('POLYGON((5 5,5 6,6 6,6 5,5 5))', -1) );
# -- both rectangles: returns true
SELECT
ST_Contains(
GeomFromText('POLYGON((0 0,0.0000001 10,10 10,10 0,0 0))', -1),
GeomFromText('POLYGON((5 5,5 6,6 6,6 5,5 5))', -1) );
# -- non-rectangle and rectangle: returns false
SELECT
ST_Contains(
GeomFromText('POLYGON((0 0,0 10,10 10,10 0,0 0))', -1),
GeomFromText('POLYGON((5 5,5.0000001 6,6 6,6 5,5 5))', -1) );
# -- rectangle and non-rectangle: returns true
SELECT
ST_Contains(
GeomFromText('POLYGON((0 0,0.0000001 10,10 10,10 0,0 0))', -1),
GeomFromText('POLYGON((5 5,5.0000001 6,6 6,6 5,5 5))', -1) );
# -- both non-rectangles: returns true
SELECT
ST_Contains(
GeomFromText('POLYGON((0 0,0 10,10 10,10 0,0 0))', -1),
GeomFromText('POLYGON((5 5,5 6,6 6,6 5,5 5))', -1) );
# -- both rectangles: returns true
SELECT
ST_Contains(
GeomFromText('POLYGON((0 0,0.0000001 10,10 10,10 0,0 0))', -1),
GeomFromText('POLYGON((5 5,5 6,6 6,6 5,5 5))', -1) );
# -- non-rectangle and rectangle: returns false
SELECT
ST_Contains(
GeomFromText('POLYGON((0 0,0 10,10 10,10 0,0 0))', -1),
GeomFromText('POLYGON((5 5,5.0000001 6,6 6,6 5,5 5))', -1) );
# -- rectangle and non-rectangle: returns true
SELECT
ST_Contains(
GeomFromText('POLYGON((0 0,0.0000001 10,10 10,10 0,0 0))', -1),
GeomFromText('POLYGON((5 5,5.0000001 6,6 6,6 5,5 5))', -1) );
# -- both non-rectangles: returns true
Paul Ramsey wrote:I think this must be arising in the "I'm a box so I can short-circuit
full computation" code. The error displays with different combinations
of square and non-square arguments.
On Jan 17, 2008, at 7:55 PM, Paul Ramsey wrote:
> I just confirmed this behavior. true/true on geos 2.2 true/false on
> geos 3.0.
> Please file this at http://trac.osgeo.org/geos, it's real, and it's
> not right.
>
> P
>
> On Jan 17, 2008, at 7:35 PM, KXK wrote:
>
>> SELECT
>> ST_Contains(
>> GeomFromText('POLYGON((0 0,0 10,10 10,10 0,0 0))', -1),
>> GeomFromText('POLYGON((5 5,5 6,6 6,6 5,5 5))', -1) );
>>
>> returns TRUE
>>
>>
>> But,
>>
>> SELECT
>> ST_Contains(
>> GeomFromText('POLYGON((0 0,0 11,11 10,10 0,0 0))', -1),
>> GeomFromText('POLYGON((5 5,5 6,6 6,6 5,5 5))', -1) );
>>
>> returns FALSE
>>
>> I thought the above would also return TRUE.
>>
>>
>> Is this behavior of ST_Contains correct?
>>
>> [VERSION INFORMATION]
>> OS: fc6
>> PostgreSQL: 8.2.4
>> PostGIS: 1.2
>> GEOS: 3.0.0
>> _______________________________________________
>> postgis-users mailing list
>> postgis-users@postgis.refractions.net
>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>
> _______________________________________________
> geos-devel mailing list
> geos-devel@lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/geos-devel
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