[postgis-users] masking out part of a MULTILINESTRING
Purvis, Charlton
cpurvis at asg.sc.edu
Thu Apr 21 07:05:34 PDT 2005
What a difference difference makes. Thanks for the help, strk. But I've
got a related question now. Hope I haven't worn out my welcome.
The difference(the_geom,***) works beautifully when done as part of the DATA
clause in a .map, but I'm ready to nuke the data directly in the table so
that I won't have to mask out the unwanted area every time.
However, when I do that, I end up w/ a total of 3 different geometries:
etopo2_bathy=# select
distinct(GeometryType(difference(the_geom,GeometryFromText('BOX3D(-87 24,-79
31)'::box3d,-1)))) from etopo2_contours;
geometrytype
--------------------
GEOMETRYCOLLECTION
LINESTRING
MULTILINESTRING
My original table has MULTILINESTRINGs and are bathymetry contours. Of
course, when I try to do an update, I get constraint problems on the
geometry type. I'm happy to drop the constraint if that's what I need to
do. And masking doesn't seem to do the trick, either. I would have thought
that a GEOMETRYCOLLECTION geometry type could handle it all, ach no.
Any ideas?
Thanks.
________________________________________
From: Purvis, Charlton [mailto:cpurvis at asg.sc.edu]
Sent: Wednesday, April 20, 2005 1:02 PM
To: 'PostGIS Users Discussion'
Subject: RE: [postgis-users] masking out part of a MULTILINESTRING
> This should be difference(geom, box);
> --strk;
Genius! Works like a charm. Thanks.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/postgis-users/attachments/20050421/a406a491/attachment.html>
More information about the postgis-users
mailing list