[postgis-users] Problem (bug?) in ST_POLYGONIZE

[Kevin Neufeld]

This is not a bug. It looks like your linestrings are not properly noded.

IE. on your line in question, the end node is POINT (697787.741 
247263.451), but the other two lines are noded at POINT 
(697787.7410000002 247263.451).

Try using snaptogrid().

SELECT geom AS the_geom 
FROM ST_Dump((
   SELECT ST_Polygonize(ST_SnapToGrid(the_geom, 0.001)) AS geom 
   FROM admin.plz));

Cheers,

-------------
Kevin Neufeld
Software Developer
Refractions Research Inc.
300-1207 Douglas St.
Victoria, B.C., V8W 2E7

Phone: (250) 383-3022
Email: kneufeld at refractions.net



Andreas Neumann wrote:
> Hello,
>
> I have a linenetwork with 15 LINESTRING() elements. I am using
> ST_POLYGONIZE() to create new POLYGON() elements. I'd expect to get 6
> polygons, but ST_POLYGONIZE() creates only 5 polygons. To make sure that
> my data is ok, I selected all start and endpoints of the LINESTRING()s and
> made sure that every start/endpoint of a LINESTRING() has two
> counterparts, which is the case.
>
> This looks like a bug to me. I would appreciate if someone else could a
> look at my data. Attached is the dump of the table and a screenshot of the
> line-network. If you load the dump, you might want to replace the owners
> with your own userid. In the screenshot, one line is marked as green. This
> is the line that is ignored by the ST_Polygonize() command.
>
> I used
> SELECT geom AS the_geom FROM ST_Dump((SELECT ST_Polygonize(the_geom) AS
> geom FROM admin.plz));
> as the SQL query.
>
> I'd appreciate any help on my problem, resp. an answer if this might be a
> bug or not.
>
> Thank you,
> Andreas
>
>   
>
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