On 1/3/2012 9:19 AM, Richard Greenwood wrote:
This seems so simple that I'm embarrassed to ask, but, putting my pride in my pocket...I want to aggregate two linestrings into one. The endpoint of the first linestring is coincident with the start point of the second. Using st_collect() or st_union() I get a multiLineString with 2 geometries. How can I get a single linestring, or a multiLineString with just 1 geometry? I cases where I aggregate linestrings that do not have coincident start/end points I do want multiLineStrings with multiple geometries. I tried the st_dump() "trick" with no better luck: SELECT label, st_numgeometries(ST_Collect (f.the_geom )) FROM ( SELECT label, (ST_Dump (wkb_geometry )).geom As the_geom from road_cl ) As f GROUP BY label Basically I'm looking for the opposite of st_multi() Thanks, Rich
Hi Rich, I think you are looking for: http://postgis.refractions.net/docs/ST_LineMerge.html -Steve _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
