DIGITAL ELEVATION MODEL DATABASE W42 - A SCALABLE SYSTEM FOR SPATIAL DATA

Digital Elevation Models (DEMs) provide elementary information for various application fields. From a global point of view, there are ma ny different sources to furnish height information of the Earth's surface. These sources can be heterogeneous in coverage, as well as in resolution, information content and quality. A database aiming at the provision of world-wide DEMs has to consider these differences in the design of the system with respect to the structure and the algorithms.The DEM database W42 is a scalable spatial database system capable of holding, extracting, mosaicing, and fusing spatial data. Design aspects for this task can be specified as holding spatial data in a unique data structure and providing unique access functions to the data. These are subject of this paper.The database's structural design is presented in a Four-Layer-Concept. Each layer provides a clearly specified interface to subsequent/preceding layers, as well as each layer is scalable in nature to meet future requirements. The scalability of the system enables the integration of the database into operational processors: at the moment it is serving as part of the geocoding-processor of the TerraSAR-X mission and as part of the generic processing chain for airborne hyperspectral data. It further will be utilized in satellite missions as an element of the Payload Ground Segment in the future. The extensions made for TanDEM-X are explained in this context.