Automatic generation of road network data from smartphone GPS trajectories

Keeping road network databases up-to-date is crucial to Geographical Information System (GIS) applications such as vehicle navigation. The vector road centerlines extracted from satellite images or in-car Global Positioning System (GPS) devices are likely to be inaccurate due to costly and labour intensive or long updating circle. The GPS data crowdsourced through smartphones provides an emerging source for refining road map due to its rich spatio-temporal coverage and reasonable level of accuracy. This thesis introduces an optimized methodology to automatically generate road network data from smartphone GPS data without using any reference maps. The horizontal accuracy of the extracted road centerlines, measured as a root mean square of 1.424 m and 1.252 m for curved and straight road segments respectively, is better than that of some existing road datasets. The outcome of this research will provide a new way of generating a more accurate and up-to-date road network databases.