On Sun, Oct 30, 2011 at 10:37:31PM -0700, Elton Chan wrote:
> Hi there,
>
> I would like to build topology for a polygon layer using postgis 2.0. The
> polygon layer contains contiguous polygons snap to each another but some are
> having some geometry error such as gap is found between polygons.
>
> Does anybody know the procedure to build topology with abovemention polygon
> data? More precisely, any procedure to convert all the polygons to line
> strings, then remove duplicate lines, and build topology and remove
> small polygons.
SELECT topology.CreateTopology('test', 4326);
SELECT topology.ST_CreateTopoGeo(ST_Collect(the_geom)) from mylayer;
Let it go while trick & treating as it'll take a lot...
A more scalable solution (the above does most work in memory) and one
which would also create the TopoGeometry objects for you to re-construct
the original point set in a value to use in your table, is the toTopoGeometry
function which takes a GEOMETRY and put it into a topology giving you back
the topologically-defined version of your GEOMETRY. Such function is yet
to be done but is planned: http://trac.osgeo.org/postgis/ticket/1017
and it is looking for co-funders (let me know if you're interested).
--strk;
() Free GIS & Flash consultant/developer
/\ http://strk.keybit.net/services.html
_______________________________________________
postgis-users mailing list
[email protected]
http://postgis.refractions.net/mailman/listinfo/postgis-users
