Abstract
The purpose of this study is to propose and test a quantitative method for evaluating prefectures as functional regions on the basis of commuter flows.
The 47 prefectures of Japan are divided into 4 types on the basis of “Internal Cohesion”, defined as the average number of commuters moving between any two sub-prefectural divisions (cities, towns, villages) located within the prefecture of interest, and the “Degree of Closure”, defined as the proportion of all commuter movements, both within a given prefecture and between that prefecture and others, that takes place within the prefecture. The 4 types are as follows:
I. The “Degree of Closure” is high and “Internal Cohesion” is strong. The prefecture is likely to constitute a complete functional region.
II. The “Degree of Closure” is low and “Internal Cohesion” is strong. The possibility is great that the prefecture, whilst itself forming a functional region, is part of a larger functional region.
III. The “Degree of Closure” is low and “Internal Cohesion” is weak. In all probability all or part of the prefecture is part of one or more larger functional regions, but cannot be considered a frnctional region in itself.
IV. The “Degree of Closure” is high and “Internal Cohesion” is weak. The possibility is great that the prefecture, whilst not in itself constituting a functional region, can be divided into several smaller functional regions.
It is found that many prefectures lie on the borderline between two or more types, which suggests that the classification should be used in conjunction with a flow map for comparison.
The method is thought to be applicable not only to commuting but also to other flows, and in addition it may be useful not only for evaluating administrative areas, but also in comparison of various functional regions.
