Chapter 7 - Applications of Computational Geometry to Geographic Information Systems

Abstract

This chapter discusses the issues related to the representation and processing of the “geometric aspects of geographic data,” with an emphasis on the application of computational geometry techniques. Geographic data are characterized by spatial properties (location, shape, size) and nonspatial properties, called “attributes,” usually expressed in textual or numerical form. Geographic information systems (GIS) as a discipline involves many different issues—such as hardware and software equipment for data acquisition, data standards, storage and transmission, database management issues (such as integrity and consistency). A broad classification of classical geometric data in a GIS can be done into: “map” data and “terrain” data. Terrain processing requires input, data models, and algorithms different from those needed for two-dimensional data. Terrain processing is a major source of geometric problems that stimulate the use of computational geometry—both in applying existing techniques, and in developing new ones. On the basis of sampled data, different models—such as, contour maps, rasters, and mathematical surface representations can be built.