OK,
In my case the linestrings I was constructing polygons from did not have aligned
start/end points (nodes), so I loaded them sequentially & snapped nodes to
pre-existing ones, to generate faces in the topology.
I did not use a topogeometry column at all, but extracted the topology faces
into a standard Postgis geometry (polygon) column.
So possibly of no use to you, I'm afraid
Cheers,
Brent
--- On Mon, 5/14/12, Luca Morandini <lmorand...@ieee.org> wrote:
From: Luca Morandini <lmorand...@ieee.org>
Subject: Re: [postgis-users] toTopoGeom performance tips
To: postgis-users@postgis.refractions.net
Date: Monday, May 14, 2012, 2:52 PM
On 05/14/2012 12:20 PM, Brent Wood wrote:
> Hi Luca,
>
> I have found it MUCH faster to throw a collection of linestrings at a topology
> (which has no snapping distance) than to add linestrings sequentially with a
> snapping distance applied to ensure polygon closure.
>
> If your data is originally polygons anyway, they are already properly closed.
> Have
> you tried doing the loading as a geometry collection instead of iteratively?
> Or is
> it loading the collection that is too slow?
I am not sure I understood you: I just threw the multipolygons at the topology
in one go, without looping:
CREATE TABLE testpolytopo(gid serial primary key, ogc_fid INTEGER);
SELECT topology.AddTopoGeometryColumn('testpolytopo', 'public', 'testpolytopo',
'topo', 'MULTIPOLYGON') As new_layer_id;
INSERT INTO testpolytopo(ogc_fid, topo)
SELECT ogc_fid, topology.toTopoGeom(wkb_geometry, 'testpolytopo', 1)
FROM lga06aaust;
(wkb_geometry column of lga066aaust contains MultiPpygons).
Regards,
Luca Morandini
Data Architect - AURIN project
Department of Computing and Information Systems
University of Melbourne
-- Regards,
Luca Morandini
Data Architect - AURIN project
Department of Computing and Information Systems
University of Melbourne
_______________________________________________
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
