The OGC definition of contains is equivalent to:
A contains B iff Every point of the B is a point of A, and the interiors
of A and B have at least one point in common.
A consequence of this definition is that "Geometries do not contain
their boundary" - if B lies wholly in the boundary of A, it is A does
*not* contain B. This is the situation that you are seeing.
Weird maybe - but that's the spec.
[EMAIL PROTECTED] wrote:
Hello,
Can you please help me, where am I wrong by using the PostGIS Function
"Contains(geometry A, geometry B)" (referring to chapter 6.1. OpenGIS
Functions of PostGIS manual)
which delivers back only points within a MULTILINESTRING except
"start-" and "endpoint" of it?
Here are some examples
This statement returns "false" even though the first POINT(7.0 50.0)
is part of the MultiLineString
SELECT Contains (GeomFromEWKT('SRID=4326;MULTILINESTRING((7.0 50.0,8.0
51.0,9.0 52.0))'), (GeomFromEWKT('SRID=4326;POINT(7.0 50.0)')) );
e.g. the "middle" point delivers what I expect="true"
SELECT Contains (GeomFromEWKT('SRID=4326;MULTILINESTRING((7.0 50.0,8.0
51.0,9.0 52.0))'), (GeomFromEWKT('SRID=4326;POINT(8.0 51.0)')) );
What I need is a function which is able to find ONE point within a
MULTILINESTRING which can be the first, last or a point between them.
I am using pgAdminIII v1.6.3, "PostgreSQL 8.2.5" and PostGIS Version
"1.1 USE_GEOS=1 USE_PROJ=1 USE_STATS=1"
Thank you very much,
Wolfgang
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Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022
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