Spatial Hierarchies and Topological Relationships in the Spatial MultiDimER Model

In Data Warehouses and On-Line Analytical Processing systems hierarchies are used to dynamically analyze high volumes of historical data using operations such as roll-up and drill-down. On the other hand, the advantage of using spatial data in the analysis process is widely recognized. Therefore, in order to satisfy the growing requirements of decision-making users it is necessary to extend hierarchies for representing spatial data. Based on an analysis of real-world spatial applications, this paper defines different kinds of spatial hierarchies and gives a conceptual representation of them. Further, we study the summarizability problem that arises for some types of hierarchies and classify the topological relationships between hierarchy levels according to the procedures required for ensuring correct measure aggregation.