Mehmet, One point does not make a linestring :) I suppose what you could do is change these to points with something of the form UPDATE ways SET linestring = ST_PointN(linestring,1) WHERE ST_NPoints(linestring) = 1 though you'll need to drop your geometry type constraint on your table first to do that. Alternatively you could just delete these records sine they are cases where ST_MakeLine had only one point in the result). Hope that helps, Regina
_____ From: [email protected] [mailto:[email protected]] On Behalf Of Mehmet Sirin Sent: Tuesday, October 27, 2009 3:13 PM To: PostGIS Users Discussion Subject: Re: [postgis-users] ST_UNION - Exception in LWGEOM2GEOS Hi, indeed there are some linestrings with only 1 Point. But I don't know how come.. after checking these points I saw that they are nothing but normal points on the way ,that means nothing special that should cause a problem. one of then is on the way 'Ahlde' -> "LINESTRING(7.3402594 52.3361277)" maybe you should know, that I imported data via osmosis and then created linestringsby using : UPDATE ways w SET linestring = ( SELECT MakeLine(c.geom) AS way_line FROM ( SELECT n.geom AS geom FROM nodes n INNER JOIN way_nodes wn ON n.id = wn.node_id WHERE (wn.way_id = w.id) ORDER BY wn.sequence_id ) c ); 2009/10/27 Paragon Corporation <[email protected]> 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 _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
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