Its a pity that st_intersection cant work on sets then it could be used to return linestrings where adjacent polygons intersect.
Well upon reflection, it can, kind of (to answer my own question): CREATE TABLE sharedlines AS SELECT ST_intersection(a.the_geom, b.the_geom) AS the_geom FROM polys a, polys b where ST_touches(a.the_geom, b.the_geom) and a.gid!=b.gid;
Probably slow though.
Surpisingly not. Much, much, quicker than st_union. st_union has given me quite a bit of grief lately, eg see http://www.webspaces.net.nz/page.php?view=polygon-dissolve-and-generalise Ill add the above to it later. peter
Am i wasting time working on this or should i wait for postgis 2.0? If the latter is their a topology primer somewhere? Peter _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
_______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
