Topology - Family of Functions

The pgRouting’s topology of a network represented with a graph in form of two tables: and edge table and a vertex table.

Attributes associated to the tables help to indicate if the graph is directed or undirected, if an edge is one way on a directed graph, and depending on the final application needs, suitable topology(s) need to be created.

pgRouting suplies some functions to create a routing topology and to analyze the topology.

Additional functions to create a graph:

• Contraction - Family of functions

Additional functions to analyze a graph:

• Components - Family of functions

The following functions modify the database directly therefore the user must have special permissions given by the administrators to use them.

• pgr_createTopology - create a topology based on the geometry.

• pgr_createVerticesTable - reconstruct the vertices table based on the source and target information.

• pgr_analyzeGraph - to analyze the edges and vertices of the edge table.

• pgr_analyzeOneWay - to analyze directionality of the edges.

• pgr_nodeNetwork - to create nodes to a not noded edge table.

Proposed

Warning

Proposed functions for next mayor release.

• They are not officially in the current release.

• They will likely officially be part of the next mayor release:

  • The functions make use of ANY-INTEGER and ANY-NUMERICAL

  • Name might not change. (But still can)

  • Signature might not change. (But still can)

  • Functionality might not change. (But still can)

  • pgTap tests have being done. But might need more.

  • Documentation might need refinement.

These proposed functions do not modify the database.

• pgr_degree – Proposed - Returns a set of vertices and corresponding count of incidet edges to the vertex.

• pgr_extractVertices – Proposed - Extracts vertex information based on the edge table information.

See Also

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