Modeling historical and future movements of spatio-temporal objects in moving objects databases

Abstract

Spatio-temporal databases deal with geometries changing over time. In general, geometries do not only change discretely but continuously; hence we are dealing with moving objects. In the past, a few moving object data models and query languages have been proposed. Each of them supports either historical movements or future movements but not both together. Consequently, queries that start in the past and extend into the future cannot be supported. To model both historical and future movements of an object, two separate concepts with different properties are required, and extra attention is necessary to avoid their conflicts. Furthermore, current definitions of moving objects are too general and vague. It is unclear how a moving object is allowed to move through space and time. For instance, the continuity or discontinuity of motion is not specified. In this paper, we propose a new moving object data model called Balloon model which provides integrated support for both historical and future movements of moving objects. As part of the model, we provide formal definitions of moving objects with respect to their past and future movements. All kinds of queries including past queries, future queries, and queries that start in the past and end in the future are supported in our model.