In our approach, the Event Calculus is used to provide a formalism that avoids the question of object timestamping by not applying time to objects. Rather, temporal behavior is reflected in events, which bring about changes in objects. Previous applications of the Event Calculus in databases are considered. An extension of the formalism to a fully bitemporal model is demonstrated. These extensions and the Object Event Calculus (OEC) form a framework for approaching temporal issues in object-oriented systems. Practical application issues as well as formal theory are described.Current GISes will support areal calculations on geographic objects, and can also describe topological relations between them. However, they lack the ability to extrapolate from historical data. The sufficiency of the temporal GIS model to support inventory, updates, quality control and display is demonstrated. Follow-up and further extensions and areas of exploration are presented at the conclusion.
['Thomas M. Schmidt', 'Frederick E. Petry', 'Roy Ladner']
The object event calculus and temporal geographic information systems