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Index
•pgRouting on PostgreSQL•Introduction•Installation•Template Creation and Use• Topological Structure•Core Features•Public Transit Implementation
(Application Specific)
Why routing on PostgreSQL?• PostGIS ships with a Shape file loader an dumper
• Various file types (Shape, MapInfo, DGN, GML, ...) can be read, converted and inserted to a PostGIS database using the OGC libraries
• A PostGIS Feature Table can be used as data source for a growing variety of map and feature server software like UMN MapServer, GeoServer, uDGI, deegree , JUMP, etc...
• The data can be accessed using standard ODBC or JDBC connectors
• Several projects have evolved around PostGIS transforming and inserting geometries from highly specialized formats like SICAD C60, EDBS, DXF, WLDGE and many more
pgRouting :an PostgreSQL Extension• pgRouting adds routing functionality to PostgreSQL.
• pgRouting is an extendible open-source library that provides a variety of tools for shortest path search as extension of PostgreSQL.
• Navigation for road networks requires complex routing algorithms that support turn restrictions and even time dependent attributes.
• Routing basically requires Network topology, which contains edges and nodes.
Core Features of pgRoutingpgRouting provides functions for:
- Shortest Path Dijkstra: routing algorithm without heuristics
- Shortest Path A-Star: routing for large datasets (with heuristics)
- Shortest Path Shooting-Star: routing with turn restrictions (with heuristics)
(Extras)- Traveling Salesperson Problem (TSP)- Driving Distance calculation (Isolines)
pgRouting Installation• On Ubuntu :
# Add pgRouting launchpad repository
sudo add-apt-repository ppa:georepublic/pgrouting
sudo apt-get update
# Install pgRouting packages
sudo apt-get install gaul-devel \postgresql-8.4-pgrouting \postgresql-8.4-pgrouting-dd \postgresql-8.4-pgrouting-tsp
• On Windows:
Download pgRouting binary package from :
http://www.pgrouting.org/download.html
Copy Share folder from binary package to :
C:/Program Files/ … /<version>/lib/
Required Topological data structure• Nodes : points with a geographic position.
• edges : represents connectivity of nodes, representing a polyline or multipolyline.
• Relations : between groups of nodes, edges and other relations which can be assigned certain properties.
• Tags can be applied to nodes, edges or relations and consist of name=value pairs.
pgRouting Template Creation and Use: To enable pgRouting functionality in a database, we
need to run :
pgRouting functions - routing_core.sql- routing_core_wrappers.sql- routing_topology.sql
TSP functions - routing_tsp.sql - routing_tsp_wrappers.sql
Driving Distance functions - routing_dd_wrappers.sql
pgRouting: Topology Calculation
• First we have to add source and target column, then we run the assign_vertex_id function ...:
-- Add "source" and "target" columnALTER TABLE ways ADD COLUMN "source" integer;ALTER TABLE ways ADD COLUMN "target" integer;
-- Run topology function (eg.)
assign_vertex_id(’<table>’, float tolerance, ’<geometry column’, ’<gid>’)
SELECT assign_vertex_id(’ways’, 0.00001, ’the_geom’, ’gid’);
Public Transit Implementation using pgRouting
•Data in-Use:▫POI tables
Bus Stops Malls and Cinema Halls Hospitals .. etc
▫Road Network▫Bus Routes
Without Change-Over from Source to Destination Route Finding
References:• Setting up pgRouting http://www.gpsfiledepot.com/tutorials/installing-and-setting-
up-postgresql-with-postgis/ 1/2
• pgRouting Workshop http://workshop.pgrouting.org/index.html
• pgRouting Documents http://www.pgrouting.org/docs/
• PostGIS in Action