[postgis-devel] [PostGIS] #1017: Implement topology.ToTopoGeom(Geometry, topology_name, layer_id)

[PostGIS]

#1017: Implement topology.ToTopoGeom(Geometry, topology_name, layer_id)
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 Reporter:  strk         |       Owner:  strk         
     Type:  enhancement  |      Status:  assigned     
 Priority:  medium       |   Milestone:  PostGIS 2.0.0
Component:  topology     |     Version:  trunk        
 Keywords:               |  
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Comment(by strk):

 Even more on empties: every TopoGeometry object needs to have a reference
 into a "relation" table. The table holds a list of components for each
 TopoGeometry object.

 Given we can't have a TopoGeometry id w/out at least one component, we'll
 need to add an empty component to have an empty TopoGeometry. Such empty
 component could have a special primitive with id 0. Although id 0 is taken
 for face components (the universal face), a TopoGeometry composed by face
 0 isn't documented as being legal.
 I guess void==universe==nirvana holds pretty nicely after all, doesn't it
 ?

 If we go there, we should probably make sure that TopoGeometry editors
 (add components, drop components) make sure to remove the special
 component 0 as soon as a real one is added and
 to re-add the special component 0 when all are removed.

 So far it all looks over-complex for just retaining typed emptiness during
 round-trip conversion from simple to topological feature...

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/1017#comment:10>
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