An event-based approach to spatial information

The notion of the location of an object at a moment of time is relatively straightforward, it is the region of space occupied by the object at that time. However, we are often concerned with the location of something over an extended period of time, as in AIice was in the room for ten minutes. Conceptualizing the location of an object in this case is much more difficult because changes of a spatial nature, i.e., changes in position, size or shape, can occur to any or all of the objects being related. Motion of course always involves changes in the location of at least one of the related objects. In this paper we propose an event-based approach to the representation of spatial information in natural language. The essential idea is to treat spatial relations as event types. The utility of this proposal is illustrated through examples of representations of locative events, various types of motion events, spatial deixis and spatial anaphora. Finally, we show how the atemporal spatial axioms of Randell, Cui & Cohn (1992) can be translated into event-based axioms for time-aware spatial reasoning.