Abstract
Ordinarily, when we divide a whole region into some homogeneous subregions, hierarchical cluster analysis is often used. But, applying the ordinary cluster analysis, such a division that unit districts belonging to a cluster form a subregion which is composed of only unit districts satisfying conditions necessary to characterize it about homogeneity among the unit districts set on the basis of the object of the division, cannot be realized. According to the object, there are also the divisions which have to satisfy such conditions about the homogeneity in a subregion. Then, in this paper, the author tried to devise a modified cluster analysis method which is able to realize such a division, and applied the method to the division of the 98 municipalities in San-in region from the standpoint of agricultural homogeneity.
In order to realize such a division, it become necessary to judge whether any two clusters satisfy the conditions or not in case that the two clusters are fused. If the two clusters don't satisfy the conditions, they cannot be fused. In this paper, applying such a criterion, the fusion was accomplished. Only the pairs of two clusters whose unit districts satisfy the conditions in case that the two clusters are fused become subjects of the fusion at each fusing stage of the clusters. Other fusing ways are the same with those of the ordinary cluster analysis method. Applying the method, the author divided the above 98 municipalities into 18 subregions (clusters) which satisfy the conditions set in the division.
The author also presented such a method that not only the conditions about the homogeneity but also the condition about contiguity mentioned in the previous paper can be satisfied in a division. The author divided the 98 municipalities into 25 subregions (clusters) which satisfy both kinds of the conditions, applying the method. The methods, which were devised in this paper, are important and effective if such conditions are necessary. But, the establishment of the conditions means that strict conditions are imposed on the fusing process. Then, we have to be careful that many subregions are necessary if we need many conditions among unit districts belonging to the same subregions.
