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.

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.

pgRouting supplies 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

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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