大都市の昼・夜間人口重心とその移動 〔短報〕

抄録

The features in population of a great city involve two phases, i. e., daytime population and nighttime population. Consequently, two kinds of centers or balanced points of population in space must be recognized corresponding to each of them. Up to this time, the center of population used to be signified as that of night-time population without any doubt, and the center of daytime population had long been put aside. However, the latter stands for the center of actual status of population in daytime, which accordingly might be called a center of citizens' activities. When they should not be coinciding at the same site in a metropolis, variuos questions must inevitably happen not only in traffic problems but also in every phase of urban adminstration.
It is not always easy, however, to find out the balanced point of daytime population in space. From the view-point taking the daytime population as a moving population, the writer believes that one can point out the balanced point in connection with the locational arrangement of terminal traffic volumes of suburbanrailways in the central area of metropolis.
Applying the theory of center of night-time population, we draw X- axis and Y- axis of our (own) accord at first. In this case, the balanced point is given with the following formula, letting Pi (Xi, Yi) stand as traffic volume at the i-th terminal station and N as the numbers of termini.
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Fig. 1 shows the centers of daytime population in Osaka both pre- and postwar, applying abovementioned method, while Fig. 3 that of night-time population and its shifting. Therefore, the distance between them is 1.5km in 1955. In comparison with this, the center of daytime population in Tokyo Central Station and that of night-time population with Shinjuku Station (Fig. 2). The distance between them is 6 KM. or about 4 times as long as the case in Osaka. Such a separation gives an additional burden on every citizen's trip on everyday life.
Through this fact we can recognize that the traffic difficulties with which Tokyo has been confronted are much severer than those of Osaka. Consequently, it would be more desirable than anything else in the city planning to give better administration on the metropolis so as to make those two kinds of centers of population as close as possible.