Geostatistical approach for controlling bus movements in Greater Lisbon using GPS

This paper describes the running development of a Location Based Application as part of an Integrated Geographic Information System ("SIIG"), made for the Lisbon Transport Delegation (DTL). The stand-alone application "busGPS", has basic GIS Viewer functionality as zooming, mapping and measuring. It allows tracking of a moving object, in this case a public bus, with a GPS receiver, saving the geographical data with the needed attributes (speed, time error, heading.) in different formats (shape and ASCII). It is connected to a database containing data on bus-routes, busstops and timetables. Out of the collected GPS-data the application recognizes the driven route or the most approximate one. It recognizes the bus-stops, where passengers entered or got out the bus and the time-delay at each station. The collected data can be saved for efficiency-control and statistics can be done to support operational performance. For this issue "busGPS" offers data analysis tools providing several statistical indicators on geographical deviations of bus routes/bus stops, time deviations of the timetables.