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