Introduction

Important

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FOSS4G routing with pgRouting tools and OpenStreetMap road data

Abstract

pgRouting adds routing functionality to PostGIS. This introductory workshop will show you how. It gives a practical example of how to use pgRouting with OpenStreetMap road network data. It explains the steps to prepare the network data, make routing queries, assign costs to the network links and modify your results through wrapper functions.

Description

Navigation for road networks requires complex routing algorithms that support turn restrictions and even time-dependent attributes. pgRouting is an extendible open-source library that provides a variety of tools for shortest path search. The library in its current version is an extension of PostgreSQL and PostGIS. It’s predecessor “pgDijkstra” was written by Sylvain Pasche from Camptocamp. It was then extended by Orkney (Japan) and renamed to pgRouting.

An introduction will give an overview of the project history, development team, infrastructure, productive environments and scope of use. The workshop will explain about shortest path search with pgRouting in real road networks and how the data structure is important to get faster routing results. Also you will learn about difficulties and limitations of implementing pgRouting functionality in GIS applications.

To give a practical example of how to perform shortest-path searches with pgRouting, the workshop makes use of OpenStreetMap road network data. The OpenStreetMap community creates their own road data that is freely available for a rapidly growing number of areas. We will use OpenStreetMap data of Capetown for this workshop. You will learn how to convert the data into the required format and how to calibrate the data with “cost” attributes. Furthermore we will explain the difference of the three main routing algorithms “Dijkstra”, “A-Star” and “Shooting-Star”.

By the end of the workshop you will have a good understanding of how to use pgRouting and how to get your network data prepared. While similar to the last years workshop “Web-based Routing: An Introduction to pgRouting with OpenLayers”, this year’s pgRouting workshop will – in regard to the students feedback – focus on pgRouting itself and network data issues. OpenLayers map client will still be used to display the route on a map.

Due to time limitation installation of pgRouting is not part of this workshop. An installation with pgRouting will be provided for you as well as the OpenStreetMap sample data for Capetown.