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:
Additional functions to analyze a graph:
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 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 - Calculates the degree of the vertices of a graph.
pgr_extractVertices – Proposed - Extracts vertex information based on the edge table information.
Indices and tables