Hierarchical aggregation procedures for interaction data

Hierarchical aggregation procedures for interaction data are considered in relation to the design of spatial systems for operational versions of interaction models. Two types of application are examined, in general terms and with reference to real situations. These deal with cases such as the delimitation of subsystems for hierarchical models where the objective is to maximise the proportion of intrazonal interaction, and cases such as the definition of internal zoning systems where an objective is to minimise the proportion of intrazonal interaction. The application of the intramax procedure is illustrated with reference to the identification of migration subsystems within Greater London and the definition of labour-market areas within Merseyside, while the application of the intramin procedure is demonstrated with respect to the design of an internal zoning system for a work-trip model of the Wirral subsystem within Merseyside.