Mehmet, It sounds like your line string might have 0 or 1 points. Use ST_NPoints(linestring) < 2 to find all linestrings with fewer than 2 points Leo
_____ From: [email protected] [mailto:[email protected]] On Behalf Of Mehmet Sirin Sent: Monday, October 26, 2009 7:24 PM To: PostGIS Users Discussion Subject: [postgis-users] ST_UNION - Exception in LWGEOM2GEOS Hi, I just tried to create a mutlilinestring out of a set of linestrings via SELECT AsText( ST_UNION(linestring) ) FROM ways w, way_tags wt WHERE w.id=wt.way_id AND wt.v='Dörnter Weg' (it lies in Osnabrück, lower saxony) but I'm getting this strange error: HINWEIS: IllegalArgumentException: point array must contain 0 or >1 elements FEHLER: Exception in LWGEOM2GEOS ********** Fehler ********** FEHLER: Exception in LWGEOM2GEOS SQL Status:XX000 Replacing wt.v='Dörnter Weg' with wt.v='Some other Streets' it works properly. So it is because of this street 'Dörnter Weg' (i got a few other ones of this kind in my database). Anybody can tell me why these sort of ways leads to a problem? thank you kind regards mehmet sirin
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