On the Spatial Scale of Industrial Agglomerations

The standard approaches to studying industrial agglomeration have been in terms of summary measures of the “degree of agglomeration” within each industry. But such measures often fail to distinguish between industries that exhibit substantially different spatial scales of agglomeration. In a previous paper, Mori and Smith [45] proposed a new pair of quantitative measures for distinguishing both the scale and degree of industrial agglomeration based on an explicit method for detecting spatial clusters. The first, designated as the global extent (GE) of industrial clusters, measures the spatial spread of these clusters (within a given country) in terms of the areal size of their essential containment, defined to be the (convex-solid) region containing the most significant subset of these clusters. The second, designated as the local density (LD) of industrial clusters, measures the spatial extent of individual clusters within their essential containment in terms of the areal share of that containment occupied by clusters. The central purpose of the present paper is to apply these two measures to the manufacturing industries in Japan, and to demonstrate how they can be used in combination to distinguish both the relative scale and degree of agglomeration exhibited by cluster patterns for each industry. In addition, the information provided by this pair of measures (GE, LD) is systematically compared to that of the most prominent summary measures currently in use. Finally, it is shown that these measures also support certain predictions of new economic geography models in the sense that shipping distances for establishments in each industry tend to be negatively (positively) correlated with the GE (LD) measures of agglomeration in these industries.