New function in Postgis topology : GetRelatedTopoGeom

[remic]

This is a ticket to host a proposal of new functions for postgis_topology. The idea is to facilitate working with mutliple layers of Topogeometry which are related.

The example use case is a (lineal) road network. A topogeometry layer could be the intersection points, with their own attributes (like type of traffic, etc.) Another topogeometry layer could be some roads of minor importance, and another topogeometry layer some road of majord importance.

The proposed function allows to get all elements of a given topogeometry layer which may be impacted by a change of geometry of a given topogeometry elements from another layer.

To be clear the function returns u as: for all x in topogeom layer X, y one topogeometry in layer Y, {u in X where x and y share at least one node}.

Please attached image issued from function testing to get a clear idea.

[remic]

A small number of images describing all the possible outputs of the function

[strk]

I think we have a function returning a set of primitive elements affecting the definition of a TopoGeometry, would an additional function to do the inverse basically get you what you're after ? It seems to be a two-steps process anyway: SourceTopoGeom → primitives → TargetTopoGeoms.

A primitives → TopoGeoms function may also serve, for example, the purpose of maintaining materialized views for quick access / indexing.

[robe]

This is a new function, can't go into a stable branch. Push —

[robe]

Milestone renamed