[postgis-users] Problem with Intersection(Geometry, Geometry)
Matt Doughty
matt.doughty at geograma.com
Wed Nov 21 03:25:27 PST 2007
Hi,
We've managed to solve the problem with the cookie cutter. The quick (and quite smart) solution was to generate a buffer of the geometries of 0 distance, thereby creating the buffer around all the geometries, lines and polygons, thus rendering insignificant the linestring problem.
Cheers,
Matt
PS. Here's the code if anybodies interested.
SELECT
buffer(INTERSECTION(<cookie>.the_geom, <cutter>.the_geom),0) AS the_geom
INTO
<output>
FROM
<cookie>,
<cutter>
WHERE
<cookie>.the_geom && <cutter>.the_geom
AND
intersects(<cookie>.the_geom, <cutter>.the_geom);
Matt Doughty
GEOGRAMA S.L.
Tel.: +34 945 13 13 72 652 77 14 15
Fax: +34 945 23 03 40
www.geograma.com
________________________________
De: postgis-users-bounces at postgis.refractions.net [mailto:postgis-users-bounces at postgis.refractions.net] En nombre de Matt Doughty
Enviado el: miércoles, 21 de noviembre de 2007 8:16
Para: postgis-users at postgis.refractions.net
Asunto: [postgis-users] Problem with Intersection(Geometry, Geometry)
Hi all,
I'm having some problems with the intersection function that I've been trying to use as a Cookie cutter command.
I've been executing the following script:
SELECT
INTERSECTION(<cookie>.the_geom, <cookie-cutter>.the_geom) AS the_geom
INTO
<output>
FROM
<cookie>,
<cookie-cutter>
WHERE
<cookie>.the_geom && <cookie-cutter>.the_geom
AND
intersects(<cookie>.the_geom, <cookie-cutter>.the_geom);
The problem it gives me is that polygons which need to be cut don't turn out right. The output retuns to the geometry column a GeometryCollection for the polygon in question. This is composed of one polygon, which is what I want, and a collection of linestrings, each of which represents a segment of the boundary of the cutting polygon, which obviously I don't want.
Has anybody come across this and how can I solve the problem?
Cheers,
Matt
Matt Doughty
GEOGRAMA S.L.
Tel.: +34 945 13 13 72 652 77 14 15
Fax: +34 945 23 03 40
www.geograma.com
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