Timber haulage routing in Ireland: an analysis using GIS and GPS

Since the late 1980s, GIS (geographical information systems) have evolved to fully enable the range of capabilities needed in transportation routing, research and management. The objective of this paper was to analyse the designation of articulated haulage routes from one central depot to various destinations around the country of Ireland in terms of road class, distance, speed and travel time and compare the results with simulated routes generated within the GIS. The analysis incorporated a digitised road map of Ireland, where the GPS routes could be overlayed, together with ESRI’s (Environmental Systems Research Institute Inc., CA) ArcGIS software. The ArcInfo Network Analyst Tool (NAT) was used to compare routes generated by Dijkstra’s routing algorithm with the actual GPS routes in terms of road classifications, distance, speed and journey time of the route selected i.e. 'destination planning', a term used here to describe the shortest optimum route based on road class, road length, road speed and route journey time. Results showed that the shortest path (in terms of distance) determined by the NAT did not replicate the actual GPS routes. However, when the NAT was manipulated and used to determine the routes based on road classes i.e. routing to higher classes of roads and not distance (by applying a cost weighting within the geometric network), then the GPS routes were over 90% similar with what was modelled within the GIS. This may allow the GIS alone to be used in the network analysis of truck routing and in particular, timber truck routing from forest harvesting site to destination timber mill in Ireland and incorporate the use of GPS for other advantages such as real-time tracking and monitoring of timber movement.