Tripod: A Comprehensive Model for Spatial and Aspatial Historical Objects

Spatio-temporal extensions to data models have been an active area of research for a number of years. To date, much of this work has focused on the relational data model, with object data models receiving far less consideration. This paper presents a spatio-historical object model that uses a specialized mechanism, called a history, to maintain knowledge about entities that change over time. Key features of the resulting proposal include: (i) consistent representations of primitive spatial and temporal types; (ii) a component-based design in which spatial, temporal and historical extensions are formalized incrementally, for subsequent use together or separately; (iii) a formally specified data model. The model can be used directly during the design of spatio-historical applications, but also forms the basis of an implementation activity developing a spatio-historical object database management system.