In the same trailing of that question and the answer, that select statement would run the function st_union in that table, without the need to create a new table or geometry column?
Sorry to use this post for this, just tought its a quite novice question, so more people could use the answer. Thx Att. George On Wed, Apr 30, 2008 at 7:20 PM, Paragon Corporation <[EMAIL PROTECTED]> wrote: > Bob, > > If I understand you correctly, I think you want to use one of the > following > > SELECT somefield, ST_Union(the_geom) > FROM sometable > GROUP BY somefield > > So lets say you want to collapse 3 rows into 1 then you just need to group > by some common field. > > E.g. if somefield = 1 for your 3 records, then those would get rolled into > the same record. > > The above will give you a LINESTRING or MULTILINESTRING. If you have all > LINESTRINGS, then may be more efficient to do this. The below will first > collapse all with common somefield into a MULTILINESTRING and then the > LineMerge will do the best it can to stitch back into a single line > string. > This is not possible with completely disjoint linestrings. > > SELECT somefield, ST_LineMerge(ST_Collect(the_geom)) > FROM sometable > GROUP BY somefield > > > If you are using the older version of Postgis, you can just take out the > ST_ > in the examples I have above. > > Hope that helps, > Regina > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Bob > Pawley > Sent: Wednesday, April 30, 2008 12:40 PM > To: PostGIS Users Discussion > Subject: [postgis-users] Line To Path > > Is there a method of converting three lines that require three rows into a > path that occupies a single row?? > > Bob Pawley > > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users > > > > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users >
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