Multi - dimensional Time Support for Spatial Data ModelsBjørn

Time has been considered from many research perspectives for applications of spatial information. However, this paper presents a generic multi-dimensional time support for spatial data models with an emphasis on geographic data. The generic time support, i.e., the temporal notions and concepts, is based on the same support applied in temporal databases and engineering databases, respectively. The generic temporal notions and concepts to handle revisions, histories, and ver-sioning of objects are deened, and applied to an example geographic data model (which is related to the standardizations within ISO/TC 211 and OpenGIS). For example, a database designer who wants to keep track of revisions of individual geographic objects can do so by assigning to these objects a single database built-in transaction time dimension. Furthermore, all kinds of objects may be deened to be temporally multi-dimensional, i.e., the database designer could, in principle, apply any number of time dimensions to the data types deened in the database schema. Hence, a value associated with diierent time dimensions can capture diierent temporal aspects and possible world semantics. The temporal model is illustrated by examples formulated using ODMG's Object Model and languages.