Spatio-Temporal Methods to Reduce Data Uncertainty in Restricted Movement on a Road Network

Much of the success of location-based applications comes from using spatial analysis in query processing and graphic visualisation. Recently, with the arrival of miniature and inexpensive GPS receivers and cellular phones, new horizons have been opened for these applications. The mobile telephone and Internet technology within the GIS environment has fostered new applications with higher degrees of user satisfaction. The advance this technology affords for data acquisition, facilitates the provision of real-time location-based services. Recently, considerable work has been undertaken in feasibility assessments and in identifying the type of services and applications that can be offered to mobile persons in an environment equipped with mobile telephones, Internet technology and GIS. No equivalent attention has been given, however, to the data that will be used for running such services. The acquired data have some degree of uncertainty mainly due to system error associated with acquisition devices and limitations in representing continuous data temporally. By focusing on restricted movement on a road network, this paper proposes a spatial registration technique to reduce the error associated with location data; it also proposes consistency checks and time registration in an effort to compensate for times when no observation is available. The processed data will also reduce the ambiguity in determining the current location of an object within the network.