The Use of the Concept of Entropy in System Modelling

The concept of "entropy" is widely used in the physical sciences and, recently, has aroused interest in the social sciences, especially in building models of urban and regional systems to be used for planning purposes. Most papers referring to the concept focus on the particular model being developed; this paper focuses on the concept itself. The first section is an introductory one which explains the use of system models in planning processes. In the second section, four views are presented of entropy: as related to probability and uncertainty; as a statistic of a probability distribution; in relation to Bayesian inference; and as a measurable system property. In the third part of the paper, the types of application of the concept are discussed in turn, and a number of other applications of the concept of "entropy" outside the usual physical science range are noted. The final section is a summary and concluding discussion, including a comparison of the approach of the statistician and entropy maximizer to system modelling.