Transcript Optimum route finder to the Point of Interest through public

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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 pgRouting
pgRouting 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 :
• On Windows:
# Add pgRouting launchpad
repository
sudo add-apt-repository
ppa:georepublic/pgrouting
sudo apt-get update
Download pgRouting binary
package from :
http://www.pgrouting.org/down
load.html
# Install pgRouting
packages
sudo apt-get install gaul-devel \
postgresql-8.4-pgrouting \
postgresql-8.4-pgrouting-dd \
postgresql-8.4-pgrouting-tsp
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" column
ALTER 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-uppostgresql-with-postgis/ 1/2
• pgRouting Workshop
http://workshop.pgrouting.org/index.html
• pgRouting Documents
http://www.pgrouting.org/docs/
• PostGIS in Action