The interest in spatial interaction models is motivated by the need to understand and explain flows of people, commodities, capital, information, or even knowledge across geographic space. By adopting a spatial interaction modeling perspective, attention is focused on interaction patterns at the aggregate rather than the individual level. The basis of modeling is the use of a discrete zone system. Discrete zone systems can obviously take many different forms, in relation to both the level of resolution and the shape of the zones. But quite often, one is forced to use administratively defined regions, such as statistical enumeration areas or the wards of a city. The level of resolution used in the spatial interaction model is in part determined by the discrete zone system.

Spatial interaction ...