An ontology for spatio-temporal databases

Spatio-temporal databases are representations of four-dimensional spatio-temporal reality. We discuss three different perspectives onto this reality: (a) the ‘god’s eye’ perspective in which spatiotemporal objects are seen as four-dimensional and non-changing, (b) the perspective of a sweeping plane dissecting four-dimensional reality into three-dimensional slices which we humans perceive the current moment; and (c) the perspective ‘from within’, which explicitly takes the existence of the change, events and processes we humans experience in our everyday live. We show that these different views have correponding spatio-temporal data models and query languages that are used to represent reality seen from the particular perspective. We argue that a spatio-temporal database system needs to be capable to switch between different views onto reality and consequently needs to provide transformations between the corresponding datastructures. We show that (a) and (b) are important for the storage of data and that (c), the view ‘from within’, is particularly important for human interactions with spatio-temporal databases, i.e., the way queries are posed to the system and the way the user expects the system to respond.