ST_Collect worked for me. I have a column of multipolygons. I can take the ST_Centroid of each multipolygon and it produces a multipoint. Don't have the SQL at hand, but it's something close to:
UPDATE table SET geom_multip=(SELECT ST_Collect(ST_Centroid(geom_multipoly)) FROM table2 WHERE ST_IsValid(geom_multipoly)) WHERE id=X Take that SQL as you need to use it. Nate On Wed, Nov 25, 2009 at 7:52 PM, Mehmet Sirin <[email protected]> wrote: > hi, is someone out there who can explain how to make several points to a > multipoint.. i tried st_union and st_collect but what comes out is a > multilinestring and geometrycollection(string(..)) respectively. > > code with which the unwilling multilinestring happens: > > select astext(st_union(c.geom_4326)) from ( > select * from (select * from( > select *,buffer(geom_4326,0.01)as buff from gc_berechnet where > name='Neuer Graben' and > gemeinde='Osnabrück')a)b, zip_coordinates zc > where contains(buff,zc.geom) )c > > > what i want to do: > 1.buffering a pointt (A) with a radius of 1km > 2.take a look which other points lie in this buffer polygon > 3.find out which point inside the buffer is nearest to the first point (A) i > buffered. > important for 3. : when having a multipoint i can easily use st_distance to > determine the closest point to point (A) > > > you can tell me how to create multipoint ? then i love you^^ > > > > leaving you kind regards > mehmet sirin c. > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > > _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
