Navigating through hierarchical change propagation in spatiotemporal queries

In spatiotemporal applications, meaningful changes vary according to object type, level of detail, and nature of application. We introduce a dynamic classification scheme and its interaction with a spatiotemporal model, to describe change propagation in spatiotemporal queries. Our classification is based on identifying three levels of change, ranging from simple verification of the continuous existence of an entity to the identification of change and the detailed description of this change. In order to provide a transformation function between these levels, we introduce a tree-based hierarchy in the spatial and temporal domains. This hierarchy is dynamic and continuously updated as new information arrives. The user has the flexibility to navigate through different resolution representations by manipulating two functions, the minimum spatial element and the minimum temporal element. In the temporal domain, queries are further more decoded as point-based and interval-based. In doing so we address the problem of time continuity within a spatiotemporal query context.