3 Conceptual Models for Spatio-temporal Applications

Improved support for modeling information systems involving time-varying, geo-referenced information, termed spatio-temporal information, has been a long-term user requirement in a variety of areas, such as cadastral systems that cap-ture the histories of landparcels, routing systems computing possible routes of vehicles, and weather forecasting systems. This chapter concerns the conceptual database design phase for such spatio-temporal information systems and presents two models, namely the spatio-temporal Entity Relationship (ER) Model and the Extended spatio-temporal Unified Modeling Language (UML) as proposed in [33,34] and [26], respectively. The conceptual design phase focuses on expressing application requirements without the use of computer metaphors. The design should be understandable to the user and complete, so that it can be translated into the logical phase that follows without any further user input. Popular conceptual models include the ER model [6], IFO [2], OMT [30], and UML [17]. For conventional administrative systems, exemplified by the “supplier-sup