Entropy, variety, economics, and spatial interaction

This article locates the gravity-type spatial interaction model within the strand of regional science that recognizes the centrality of heterogeneity for spatial analysis. Wilson's entropy-maximizing (EM) formulation is considered alongside that from random utility (RU) functions as bases for theorizing the interaction model and the role of diversity in spatial processes. It highlights ambiguities in the relationship of the EM approach to causality, particularly in relation to assumed constraints on modelled outcomes, and the significance of variety as a concept emerging from the RU approach to analysis of spatial interactions. Taking as an example the challenge of translating central place theory into a heterogeneous form, it argues the need for spatial modelling to engage more closely with the substantive explanatory concerns and hypotheses of mainstream geographers and regional scientists.