So I reprocessed the two polygons below in a topology have tolerance=0. However I still get the two same geometries in ovlp.test03_topo. I was expecting three polygons: 1 non-overlapping part for each and 1 representing the overlapping shared part with I don't know which attribute.
I though topology would prevent the insertion of any overlapping part and remove (or aggregate) them. I thought at least the mbr column of the topo3.face table would contain the three geometries but no, they are just mbrs... How can I fix my overlapping problem with topology? Pierre > So as of r9630 this topology of yours builds. > Of course your input geometries are not going to being fully > represented as the tolerance of 10 units on the topology is > chewing them badly. > > Use tolerance with care ! > > Let me know how your next topos go :) > > --strk; > > ,------o-. > | __/ | Delivering high quality PostGIS 2.0 ! > | / 2.0 | http://strk.keybit.net - http://vizzuality.com > `-o------' > > > On Wed, Apr 11, 2012 at 02:53:07PM -0400, Pierre Racine wrote: > > An even simpler example leads to another type of error: > > > > SELECT CreateTopology('topo3',0, 10); > > > > DROP TABLE IF EXISTS ovlp.test03; > > CREATE TABLE ovlp.test03 AS > > SELECT 1 id, ST_GeomFromText('POLYGON((0 1, 2 2, 2 0, 0 1))') geom > > UNION ALL > > SELECT 2 id, ST_GeomFromText('POLYGON((1 1, 3 2, 3 0, 1 1))') geom > > > > CREATE TABLE ovlp.test03_topo (id integer); > > > > SELECT AddTopoGeometryColumn('topo3', 'ovlp', 'test03_topo', 'topo', > 'POLYGON'); -- 1 > > > > INSERT INTO ovlp.test03_topo (id, topo) > > SELECT id, topology.toTopoGeom(geom, 'topo3', 1) > > FROM ovlp.test03 > > > > gives: > > > > ********** Error ********** > > > > ERROR: SQL/MM Spatial exception - edge crosses node. > > SQL state: P0001 > > Context: PL/pgSQL function "topogeo_addpoint" line 96 at assignment > > PL/pgSQL function "topogeo_addlinestring" line 125 at assignment > > SQL statement "SELECT array_cat(edges, array_agg(x)) FROM ( select > topology.TopoGeo_addLinestring(atopology, rec.geom, tol) as x ) as foo" > > PL/pgSQL function "topogeo_addpolygon" line 27 at assignment > > SQL statement "INSERT INTO topo3.relation(topogeo_id, layer_id, > element_type, element_id) SELECT 2, 1, 3, topogeo_addPolygon('topo3', > '01030000000100000004000000000000000000F03F000000000000F03F0000000 > 00000084000000000000000400000000000000840000000000000000000000000 > 0000F03F000000000000F03F'::geometry, 10);" > > PL/pgSQL function "totopogeom" line 129 at EXECUTE statement > > > > Pierre > > > > > -----Original Message----- > > > From: postgis-users-boun...@postgis.refractions.net [mailto:postgis-users- > > > boun...@postgis.refractions.net] On Behalf Of Pierre Racine > > > Sent: Wednesday, April 11, 2012 2:40 PM > > > To: PostGIS Users Discussion > > > Subject: Re: [postgis-users] Method to remove overlaps in a layer > > > > > > So I have been creating a very simple example based on the example in the > > > toTopoGeom() documentation page: > > > > > > http://www.postgis.org/documentation/manual-svn/toTopoGeom.html > > > > > > SELECT CreateTopology('topo1',31467, 10); > > > > > > CREATE TABLE ovlp.test02_topo (id integer); > > > > > > SELECT AddTopoGeometryColumn('topo1', 'ovlp', 'test02_topo', 'topo', > > > 'POLYGON'); > > > > > > INSERT INTO ovlp.test02_topo (id, topo) > > > SELECT id, topology.toTopoGeom(geom, 'topo1', 1) > > > FROM ovlp.test02 > > > > > > And I get: > > > > > > ********** Error ********** > > > > > > ERROR: interpolate_point4d: invalid F (1) > > > SQL state: XX000 > > > Context: PL/pgSQL function "st_modedgesplit" line 94 at assignment > > > PL/pgSQL function "topogeo_addpoint" line 91 at assignment > > > PL/pgSQL function "topogeo_addlinestring" line 132 at assignment > > > SQL statement "SELECT array_cat(edges, array_agg(x)) FROM ( select > > > topology.TopoGeo_addLinestring(atopology, rec.geom, tol) as x ) as foo" > > > PL/pgSQL function "topogeo_addpolygon" line 27 at assignment > > > SQL statement "INSERT INTO topo1.relation(topogeo_id, layer_id, > > > element_type, element_id) SELECT 5, 1, 3, topogeo_addPolygon('topo1', > > > > '0103000020EB7A0000010000000800000000000080FD384B4100000000F46154 > > > > 4100000000D84B4B41000000405069544100000000B55D4B41000000005C6354 > > > > 4100000000BD594B4100000000965B544100000000C8694B4100000000625554 > > > > 4100000080E15C4B4100000080474D544100000080ED404B41000000006C5054 > > > 4100000080FD384B4100000000F4615441'::geometry, 10);" > > > PL/pgSQL function "totopogeom" line 129 at EXECUTE statement > > > > > > I join a picture of the original layer to be converted to a topologic > > > layer. > > > > > > I'm still at beta 5... Should upgrading solve that particular problem? > > > > > > Pierre > > > > > > > > So what would be the normal/easiest steps to convert a messy polygon > > > > coverage into a clean topology? Is it documented somewhere? > > > > > > > > > > My guess: > > > > > > > > > > 1- SET search_path TO topology,public; > > > > > > > > You shouldn't need this, when you load topology.sql you should > > > > get "topology" already appended to the end of the search_path > > > > associated with the database. > > > > > > > > > 2- SELECT CreateTopoGeom('test') > > > > > > > > Yep. > > > > > > > > > 3- SELECT toTopoGeom(geom, 'test', 1) > > > > > FROM mymessyone; > > > > > > > > You didn't create a layer, see AddTopoGeometryColumn. > > > > The third argument is a layer id, as returned by that function. > > > > > > > > > or > > > > > > > > > > SELECT ST_CreateTopoGeo('test', geom) > > > > > FROM mymessyone; > > > > > > > > This one only works starting with an empty topology so > > > > you'll need to pass it a full collection: > > > > > > > > SELECT ST_CreateTopoGeo('test', ST_Collect(geom)) FROM mymessyone; > > > > > > > > But I'd recommend using toTopoGeom instead, to keep the linking > > > > between attributes and geometries. > > > > > > > > > What happens when a polygon to be added to the topology overlaps a > > > > polygon already in the topology? > > > > > > > > Two overlapping rectangles would produce a total of 3 faces. > > > > If you're returning TopoGeometry objects (your step 2) both > > > > of them will be defined by 2 faces, having one face in common. > > > > > > > _______________________________________________ > > 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
