[postgis-users] Convert lines to polygon

[Michael Fuhr]

On Mon, Aug 21, 2006 at 02:57:34PM +0200, Vera Schulze wrote:
> this is the query:
> SELECT oid, ogc_fid, astext(polygonize(the_geom)) FROM 
> countries_dcw_test WHERE cntry_code = 'QT' GROUP BY oid, ogc_fid
> 
> And I attached the data as csv-file.
> 
> There are 27 records and originally they are of type line. Some of the 
> records contain start and endpoint, the others doesn't.

I think I understand: some of the linestrings form closed figures
like islands, while others are portions of a boundary and aren't
closed.  Is that right?

Instead of grouping by oid and ogc_fid, try polygonizing all of the
geometries into a single geometry collection, then use dump() to
extract the individual polygons.  This works for me with your dataset:

SELECT astext(geom)
FROM dump((
  SELECT polygonize(the_geom)
  FROM countries_dcw_test
  WHERE cntry_code = 'QT'
));

Will something like that work for you?

-- 
Michael Fuhr