2. About The Workshop

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This workshop uses several FOSS4G tools. Most of FOSS4G software is related to other open source projects and it would go too far to list them all here.

2.1. pgRouting Overview

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pgRouting extends the PostGIS / PostgreSQL geospatial database to provide geospatial routing functionality.

Advantages of the database routing approach are:

  • Data and attributes can be modified by many clients, like QGIS and uDig through JDBC, ODBC, or directly using Pl/pgSQL. The clients can either be PCs or mobile devices.
  • Data changes can be reflected instantaneously through the routing engine. There is no need for precalculation.
  • The “cost” parameter can be dynamically calculated through SQL and its value can come from multiple fields or tables.

pgRouting library contains following core features:

pgRouting is Open Source, available under the GPLv2 license and is supported and maintained by Georepublic, iMaptools and a broad user community.

pgRouting is an OSGeo Community Projects project of the OSGeo Foundation and included on OSGeoLive.

Website:http://www.pgrouting.org
OSGeoLive:https://live.osgeo.org/en/overview/pgrouting_overview.html

2.2. osm2pgrouting Overview

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osm2pgrouting is a command line tool that imports OpenStreetMap data into a pgRouting database. It builds the routing network topology automatically and creates tables for feature types and road classes. osm2pgrouting was primarily written by Daniel Wendt and is now hosted on the pgRouting project site.

osm2pgrouting is available under the GPLv2 license.

Wiki: https://github.com/pgRouting/osm2pgrouting/wiki

2.3. OpenStreetMap Overview

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“OpenStreetMap is a project aimed squarely at creating and providing free geographic data such as street maps to anyone who wants them. The project was started because most maps you think of as free actually have legal or technical restrictions on their use, holding back people from using them in creative, productive or unexpected ways.”

(Source: http://wiki.openstreetmap.org/index.php/Press)

OpenStreetMap is an adequate data source for pgRouting, because has no technical restrictions in terms of processing the data. Data availability still varies from country to country, but the worldwide coverage is improving day by day.

OpenStreetMap uses a topological data structure:

  • Nodes are points with a geographic position.
  • Ways are lists of nodes, representing a poly line or polygon.
  • Relations are groups of nodes, ways and other relations which can be assigned certain properties.
  • Properties can be assigned to nodes, ways or relations and consist of name=value pairs.

OpenStreetMap website: http://www.openstreetmap.org