Snapping has a few limitations. One is that only vertices in the target are considered as snap points, so you'll never get a vertex of first geometry snapped against a segment of the second.
See if this could explain your problem. --strk; On Wed, Jul 11, 2012 at 12:50:30PM +0000, Astrid Bjørnerød wrote: > I want some polygons (with attribute artype=21) to snap into some > neighbor-polygon. I have set the tolerance to 5m. > Put not all of the polygons in the result has been snapping, the gap is under > the tolerance. > The sql: > create table test_ar5jm.snipsnap AS SELECT > p1.jmsign,ST_Union(ST_Buffer(ST_Snap(p1.geo,p2.geo, 5),0)) as geo > FROM test_ar5jm.temp_aij_flate > AS p1 CROSS JOIN test_ar5jm.temp_aij_flate As p2 > WHERE p1.artype = 21 > GROUP BY p1.jmsign; > > Figures from QGis before snapping and after snapping in attachedment. > > Vennlig hilsen > Astrid Bjørnerød > > Seksjon Geomatikk > ------------------------------------------- > Norsk institutt for skog og landskap > Pb 115, NO-1431 Ås > T (+47) 64 94 96 96 > F (+47) 64 94 80 01 > ------------------------------------------- > www.skogoglandskap.no<http://www.skogoglandskap.no> > ------------------------------------------- > _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users