Equilibrium and Nonequilibrium Statistical Thermodynamical Approaches to Modeling Spatial Interaction Dynamics

Spatial interaction modeling can be embedded in the framework of statistical thermodynamics. This has been shown in part by Wilson and by Erlander, in particular. However, to complete the embedding, it is necessary to ask the dynamic question of how a migratory population evolves over time from one (observed) distribution at time t₀ to another (observed) distribution at time t₁, rather than just the question of how many people who started in one area at t₀ ended in another at t₁—with no regard to the intermediate locations of the migrants. The manner in which such evolutionary processes are addressed in the context of equilibrium and nonequilibrium thermodynamics serves as a basis for extending the spatial interaction model of human movement.