Deriving Spatiotemporal Relations from Simple Data Structure

A spatiotemporal data model is incomplete without three components: classes, consistency constraints, and operators. Classes define the structure of the model, constraints enforce consistency in the model, and operators operate on the structure of the model. In the past, many models have been proposed, but most of them discussed the classes. The studies on operators for spatiotemporal data models are not abundant. Operators used to query spatial, temporal, and spatiotemporal relations are the focus of this paper. Relations in the spatiotemporal databases can be categorized into three groups: spatial, temporal, and spatiotemporal relations. Spatial relations that are valid for a certain time period are called spatiotemporal relations. These spatiotemporal relations are based on a cell-tuple-based spatiotemporal data model (CTSTDM). Spatiotemporal relations can be classified into five groups: metric, topological, order, set oriented, and Euclidean. This paper elaborates on the topological relations (spatiotemporal topology) derived from a simple temporal cell-tuple structure. The operator, operand(s), results, and syntax of the spatiotemporal relations are defined. By employing relational algebra, spatiotemporal relations (boundary, contains, overlaps, etc.) can be derived from the cell-tuplebased spatiotemporal data model. In the past, two common approaches have usually been employed to obtain topological relations. The first is called explicit, and the other is implicit. Both approaches have advantages and disadvantages. The cell-tuple-based spatiotemporal data model stores spatiotemporal topology implicitly, which is more appropriate for spatiotemporal and network databases. The paper concludes with limitations of this implicit topology approach and recommendations for future work.