[geos-devel] Re: [postgis-users] ST_Contains doesn't work?

[KXK]

Paul & Ben J.


I found a quick solution for this "Contains" problem.

These 3 lines below should be deleted to fix this bug.

source/geom/Geomtry.cpp

bool
Geometry::contains(const Geometry *g) const
{
.
.
.
	if (isRectangle()) {
		return predicate::RectangleContains::contains((Polygon&)*this, *g);
	}
// Delete from here
	if (g->isRectangle()) {
		return predicate::RectangleContains::contains((const Polygon&)*g, *this);
	}
// Delete until here
.
.
}



The reason why I thought of deleting these 3 lines was:

The 1st argument should be passed as the 2nd argument,
and the 2nd argument should be passed as the 1st argument,
because it should varify if *this contains *g. Not the other way around.

BUT, predicate::RectangleContains::contains method accepts the 1st
argument only being a rectangle.
So, passing *this as the 1st argument is not acceptable since *this is
not guaranteed as a rectangle; it is just a geometry.


I will put this info to the below site, too.
http://trac.osgeo.org/geos/

What do you think about the solution? I need your feedbacks.


Good Day,

KXK


2008/1/18, KXK <vivahome2 at gmail.com>:
> Paul
>
>
> Thanx for a quick reply.
>
> At http://trac.osgeo.org/geos, I issued a ticket whose number is #171.
>
>
> KXK
>
> 2008/1/18, Paul Ramsey <pramsey at refractions.net>:
> > 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 at postgis.refractions.net
> > >> http://postgis.refractions.net/mailman/listinfo/postgis-users
> > >
> > > _______________________________________________
> > > geos-devel mailing list
> > > geos-devel at lists.osgeo.org
> > > http://lists.osgeo.org/mailman/listinfo/geos-devel
> >
> > _______________________________________________
> > geos-devel mailing list
> > geos-devel at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/geos-devel
> >
>