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I have created a PostGIS topology table by importing a shapefile and following a tutorial online. I can now load the edges and nodes into QGIS. But I am not seeing the edges and nodes tables anywhere when I look at the database in PgAdmin. Where are they being stored? I am making modifications to the edges and nodes tables in QGIS and I need to verify that they are being added properly.

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Topology functions are stored in the topology schema, topology data (edges, faces, nodes, relations) are stored in a user-defined schema, and relations (topo id, layer id, element id, element type) are stored with the geometry data.

From the command line you can view tables in the topology schema with:

SELECT * 
FROM information_schema.tables 
WHERE table_schema = 'topology';

With pgAdminIII it looks like this:

enter image description here

Once you create a topology and add data to a layer in that topology, then the topology.topology and topology.layer tables will each have one record in them.

Creating the toplogy with CreateTopology would look like this:

SELECT topology.CreateTopology('me_topo', 4326, 0.0001);

And adding data to that topology with AddTopoGeometryColumn would look something like this:

SELECT topology.AddTopoGeometryColumn('me_topo', 'public', 'me_counties', 'topo', 'MULTIPOLYGON');

Finally set the topology data in the new topo column with toTopoGeom:

UPDATE me_counties SET topo = topology.toTopoGeom(geom, 'me_topo', 1); 

Now you will be able to see the edge, face and node data in the me_topo schema:

enter image description here

  • 1
    Actually the topology schema only contains the topology functions and support tables. The data that is in the topology is stored in the schema specified in the CreateTopology command. In that example above you'll get a schema called "me_topo" and in that schema you'll find tables with edges, nodes, faces, and relations. – HeyOverThere Feb 23 '17 at 20:47
  • You got me @HeyOverThere! Edited to improve the explanation of what functions and data live where. – katahdin Feb 23 '17 at 21:06
  • @1saac did this answer your question? If so please select it as answered :) – katahdin Feb 24 '17 at 14:41

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