From Digital Elevation Model to Topographic Information System

The term "Topographic Information System (TIS)" is defined in the first section as one of three categories of spatial information systems. In the second section, a new solution is outlined for the mathematical surface modelling of a digital elevation model (DEM), as a component of a TIS. In the third section, additional data (digital orthophotos, geo-coded satellite images, scanned topographic maps and three-dimensional vectors with numerous attributes) which serve to create a TIS from a DEM are discussed. Some thoughts on an object-oriented database model for a TIS are introduced in the last section. A "vertical" topology is introduced here, in addition to edge-node topology and surface-topology, and the inheritance of the numerous attributes in a TIS is discussed.