Multi - dimensional Time Support for Spatial Data Models

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 versioning of objects are de ned, 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 de ned to be temporallymulti-dimensional, i.e., the database designer could, in principle, apply any number of time dimensions to the data types de ned in the database schema. Hence, a value associated with di erent time dimensions can capture di erent temporal aspects and possible world semantics. The temporal model is illustrated by examples formulated using ODMG's Object Model and languages.