Subject(s): Geographic information systems -- Geographic information systems and society -- Data Models and Axioms: Formal Abstractions of Reality -- Geographical Data in the Computer -- Data Input, Verification, Storage, and Output -- Creating Continuous Surfaces from Point Data -- Optimal Interpolation using Geostatistics -- The Analysis of Discrete Entities in Space -- Spatial Analysis using Continuous Fields -- Error Propagation in Numerical Modelling -- Fuzzy Sets and Fuzzy Geographical Objects -- Errors and Quality Control -- Current Issues and Trends in GIS