Abstract
When we divide a whole region into homogeneous subregions, cluster analysis is often used and each unit district is permitted to belong to only one subregion in the analysis method. However, according to the object of the division, there are cases that unit districts must be permitted to belong to plural subregions. If it is permitted, we can grasp the many-sided characteristics about similarity among unit districts. Then, in this paper, the author devised the method for dividing whole region into subregions in which unit districts are permitted to belong to plural subregions and applied it to the homogeneous division of the whole 98 municipalities in San-in region.
In order to realize such a division, the author adopted the following way:
First, the whole region is divided into homogeneous subregions in application with cluster analysis provided the condition that unit districts belonging to each cluster must satisfy conditions of their homogeneity with one another. If unit districts belonging to each subregion are necessary to be contiguous with one another, contiguity constraints are also provided to the duster analysis. In this paper, the author adopted subregions made up in the previous paper as those before unit districts belonging to other subregions are included.
Next, for each subregion, unit districts that are belonging to other subregions but satisfy the same conditions of the homogeneity if included to it are included one after another to it. Doing so, each subregion becomes to include more unit districts. As a result, unit districts belonging to plural subregions are generated. In the case to consider also the contiguity constraints, unit districts satisfuing not only the conditions of the homogeneity but also the contiguity constraints become the objects for the inclusion.
As a result, it has become clear that the subregions made up in application with the method show the many-sided characteristics about similarity among unit districts compared with the subregions made up in application with usual dividing methods, in which unit districts are not permitted to belong to plural subregions. Moreover, in the case to consider the contiguity constraints too, the method is also useful to make up intermediate subregions between two subregions.
