Temporal Objects for Spatio-Temporal Data Models and a Comparison of Their Representations

Martin Erwig, Markus Schneider, and Ralf Hartmut Güting
Praktische Informatik IV, Fernuniversität Hagen, D-58084 Hagen, GERMANY,
{erwig, markus.schneider, gueting}@fernuni-hagen.de
 Abstract: Currently, there are strong efforts to integrate spatial and temporal database technology into spatio-temporal database systems.  This paper views the topic from a rather fundamental perspective and makes several contributions.  First, it reviews existing temporal and spatial data models and presents a completely new approach to temporal data modeling based on the very general notion of temporal object.  The definition of temporal objects is centered around the observation that anything that changes over time can be expressed as a function over time.  For the modeling of spatial objects the well known concept of spatial data types is employed.  As specific subclasses, linear temporal and spatial objects are identified.  Second, the paper proposes the database embedding of temporal objects by means of the abstract data type approach to the integration of complex objects into databases.  Furthermore, we make statements about the expressiveness of different temporal and spatial database embeddings.  Third, we consider the combination of temporal and spatial objects into spatio-temporal objects in (relational) databases.  We explain various alternatives for spatio-temporal data models and databases and compare their expressiveness.  Spatio-temporal objects turn out to be specific instances of temporal objects.

Keywords: Spatial, temporal, spatio-temporal, data types, moving objects, moving point, moving region

Published: Advances in Database Technologies (ER '98 Workshop on Spatio-Temporal Data Management), LNCS 1552, 454-465, 1998.