Abstract

Spatio-temporal databases deal with geometries changing over time. In general, geometries cannot only change in dis-crete steps, but continuously, and we are talking about moving objects. If only the position in space of an object i s relevant, then moving point is a basic abstraction; if also the extent is of interest, then the moving region abstraction captures moving as well as growing or shrinking regions. We propose a new line of research where moving points and moving regions are viewed as three-dimensional (2D space + time) or higher-dimensional entities whose structure and behavior is captured by modeling them as abstract data types. Such types can be integrated as base (attribute) data types into relational, object-oriented, or other DBMS data models; they can be implemented as data blades, cartridges, etc. for ex-tensible DBMSs. We expect these spatio-temporal data types to play a similarly fundamental role for spatio-temporal data-bases as spatial data types have played for spatial databases. In this paper we consider the need for modeling spatio-temporal data types on two different levels of abstraction. 1