As I understand from the code, this will create a node/point if my line "self intersects", but I need to brake my line into N new lines where it intersects with any other line from the same table.
On Wed, Mar 28, 2012 at 3:31 PM, Horst Düster <horst.dues...@kappasys.ch> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi > > if you work with PostGIS < 2.0 you can use the cleangeometry() function. > > http://www.kappasys.ch/pgtools/cleangeometry/cleanGeometry.sql > > Regards > Horst > > Dr. Horst Düster > Kappasys > Alte Bernstrasse 13 > CH-4500 Solothurn > > Tel.: +41 (0) 32 514 00 40 > Mobil: +41 (0) 76 408 51 06 > eMail: horst.dues...@kappasys.ch > skype: horstduester > Twitter: moazagotl > Web: www.kappasys.ch > > lat: N 47° 12' 06.408" lon: E 7° 32' 13.740" > > Am 28.03.2012 12:29, schrieb Pavel Iacovlev: >> Hello, >> >> Anyone has any ideas/tips of how to break lines at intersections ? >> I have a a layer of lines and I want to break them at intersections >> with them selfs, also (not that important but would be nice) break >> lines forming a collapsed loop, for example 0.0;1.0;0.0 is broken at >> 1.0. >> >> Currently this can be done in grass with v.clean tool=break,rmdupl but >> it's relatively hard to add GRASS to a web app. >> >> So far I came up with this query and out of ideas right now: >> >> SELECT DISTINCT >> gid, >> ST_AsText(intersect_geom), >> ST_Line_Locate_Point(GeometryN(the_geom, 1), intersect_geom) as point_loc1 >> FROM >> >> (SELECT a.gid, ST_Intersection(a.the_geom, b.the_geom) AS >> intersect_geom, a.the_geom >> FROM roads as a, roads as b >> WHERE ST_Intersects(a.the_geom, b.the_geom) AND (a.gid = 1) >> ) AS res1 >> >> WHERE GeometryType(intersect_geom) = 'POINT' -- Need support for >> MULTILINESTRINGS, take start and end point ? >> ORDER BY point_loc1 >> >> which has the following result: http://jsfiddle.net/9RJ8a/ >> I have the line, and the point positions on the line, but I can't get >> around how to create my NEW broken lines with >> ST_Line_Substring(geometry a_linestring, float startfraction, float >> endfraction) >> >> Any suggestion of how to accomplished this ? is the approach correct ? >> any other ideas ? >> _______________________________________________ >> postgis-users mailing list >> postgis-users@postgis.refractions.net >> http://postgis.refractions.net/mailman/listinfo/postgis-users > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.11 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ > > iQEcBAEBAgAGBQJPcwSiAAoJENJq1wkKM7pS6NwH/3PzIeSfjG29wfrPx4mLu7gS > 6gAYWk6Lsfp4kUEoy6uJdtGz6iFn3vY2blz1cA9diUrjw00O8m5/8IVFuI0jdyLM > j6tzDbyB7jmXyF6F3TLKfnAakVGenhbcXTeHRL3ojAiKcq8UGsRDQYviQ3WZK9sY > EXP9wJIunhawILOfFXEO68AcRDPLZcaLtZAE/qj4yY+p538M/8PNfuK2rBw6fcVO > dPcug4wDewciPYQBcgKdbRpXtpfh9ytq4xYV16aAA8wVg4lFicldIm4cm8mytOrb > 0bYYyFmAHtpBQ2Hv6A7eMxywzF8iQmu8oPl1I6ihPwol3VQ/Tws+nAKbfGKs3bs= > =FgwT > -----END PGP SIGNATURE----- > _______________________________________________ > 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
