Post-processing GPS-tracks in reconstructing travelled routes in a GIS-environment: network subset selection and attribute adjustment

Abstract

The exact distance and routes travelled on an individual level are essential variables in determining the effectiveness of ‘soft’ transport demand management strategies. The ability to track individuals in great spatial detail by means of Location Aware Technologies such as GPS has opened avenues for gathering these data with great precision. Route reconstruction with positional data is typically done by a process referred to as map-matching; however, despite the large number of real-time map-matching algorithms developed, few studies have developed a post-processing map-matching algorithm in a Geographic Information Systems (GIS)-environment. This paper presents two GIS-based map-matching methods that predominantly use a digital road network with speed and directionality attributes for route reconstruction of raw GPS-trajectories. The methodologies were tested for a data set in which actual routes travelled were known. Both explored procedures, the ‘Connected Subset’ assignment procedure based on network subset selection and the ‘Impedance Reduction’ assignment procedure based on attribute adjustment, provide accurate results. In addition, both procedures effectively deal with commonly GPS-induced problems such as measurement gaps and positional drift.