A family of spatial interaction models, and associated developments
This paper shows that the gravity model is not a single model but that there is a whole family of spatial interaction models. The properties of this family are outlined in some detail. Basic concepts of such models can be developed in a variety of ways, and these are illustrated. The paper then outlines a number of other theoretical developments, and is particularly concerned with the disaggregation of such models, with the incorporation of time variables, and with the relation of spatial interaction, to more general, models. Uses of spatial interaction models are outlined briefly and the final section of the paper draws a number of conclusions and presents a summary.