No, ST_Intersects is just a 2D only operation. Extra dimensions are not accounted for.
Once you get into operations on polygons, it becomes impossible to do 3D ops, since the 3D volumetric shape of a polygon-with-zs is ambiguous for most cases. P. On Tue, Oct 13, 2009 at 11:33 PM, Brian Modra <[email protected]> wrote: > 2009/10/14 Bruno Friedmann <[email protected]>: >> Hi all, I've just discover that I've a trouble (another) with 3D. >> >> I've 2 set of records, one is full, the other have some hole inside. >> I'm looking a way to extract ( building some 3d polygons or 3d lines ) point >> that are in the first full set, not present in the >> second. ( Find the hole ) >> >> I was thinking about using st_intersects &| st_disjoint but I realize that >> >> select st_disjoint( >> st_setsrid(st_makepoint(585000, 226500, 0),21781), >> st_setsrid(st_makepoint(585000, 226500, 100),21781) >> ) >> , >> st_intersects( >> st_setsrid(st_makepoint(585000, 226500, 0),21781), >> st_setsrid(st_makepoint(585000, 226500, 100),21781) >> ) >> >> return false,true ... which should return true,false. > > I think whats happening is that although the coords are stored > x,y,z... the calculations project them first. > So its not a 3D comparison. > >> >> Did I need to invent my st_intersects3D function which would you >> st_intersects with X,Y and an another check on Z equality ? >> >> Did you think it's a good idea. >> >> PS : I'm using postgis 1.3.5 now, did the 1.4.0 release could help me in >> this case ? >> >> Many thanks in advance for your precious advise >> >> >> -- >> >> Bruno Friedmann >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> > > > > -- > Brian Modra Land line: +27 23 5411 462 > Mobile: +27 79 69 77 082 > 5 Jan Louw Str, Prince Albert, 6930 > Postal: P.O. Box 2, Prince Albert 6930 > South Africa > http://www.zwartberg.com/ > _______________________________________________ > 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
