On Thu, Jan 11, 2007 at 01:52:05PM -0800, Anne-Leslie Dean wrote:
> I've built two (valid, per GEOSisValid) geometries
> using GEOSGeom_createLineString. Each one contains
> two coordinates (a single line segment). Together the
> two geometries form a plus (+), i.e. two line
> segments, crossing each other in the center.
>
> Upon calling GEOSIntersects, GEOSCrosses and
> GEOSOverlaps, they all return false. This is not what
> I expected.
>
> Am I making some incorrect assumptions about what to
> expect?
This is what to expect:
=# select intersects(a, b), crosses(a, b), overlaps(a,b) from
( select 'LINESTRING(-10 0, 10 0)'::geometry as a,
'LINESTRING(0 10, 0 -10)'::geometry as b ) as foo;
intersects | crosses | overlaps
------------+---------+----------
t | t | f
Results obtained with GEOS="3.0.0rc4-CAPI-1.3.2" (PostGIS linked against C-API).
What GEOS version are you using ?
--strk;
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