[postgis-users] topology, joining attributes

[Rémi Cura]

Hey,
the mapping is not direct.
Schematically,
it would be :
your topogeom -> (topogeom_id) relation table (element_id)-> (face_id) face.
Maybe this schema can help you :
http://trac.osgeo.org/postgis/attachment/ticket/2578/postgis_topology_data_model_explained%20%286%29.png

Your querry could look like this:

SELECT my_topogeom, f.face_id
FROM my_table AS mt
INNER JOIN relation AS r ON (((mt.mytopogeom).id ,
(mt.mytopogeom).layer_id)) = (r.topogeo_id, r.layer_id  )
INNER JOIN face AS f ON (r.element_id = f.face_id)

Cheers,
Rémi-C


2014-07-23 3:17 GMT+02:00 Richard Greenwood <richard.greenwood at gmail.com>:

> I have a table of simple polygons named work.aliquot with a primary key
> named ogc_fid and several columns of attribute data. I created a topology
> and added a topogeometry column and then:
>
> UPDATE aliquot SET topogeom = toTopoGeom(wkb_geometry, 'aliquot_topology',
> 1);
>
> The various fields and tables all appear to have been populated correctly.
>
> Now I need to join the attributes from the work.aliquot table to
> aliquot_topology.face but I'm stuck. I was guessing that
> aliquot_topology.relation would be the route but after some experimenting
> that seems not to be the case, or else I'm not getting it. Do I have to do
> a spatial join to get my attributes from the source table into my new
> topology?
>
> Thanks,
> Rich
>
> --
> Richard W. Greenwood, PLS
> www.greenwoodmap.com
>
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