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Demographic gravitation is a concept of "social physics",〔Stewart, J.Q. "The Development of Social Physics", American Journal of Physics, Vol 18 (1950), pp. 239-253〕 introduced by Princeton University astrophysicist John Quincy Stewart〔Vecchia, Karla J., ''John Q. Stewart Papers (C0571)1907-1970s A Finding Aid, Manuscripts Division Department of Rare Books and Special Collections'', Princeton University Library, 2004 ()〕 in 1947.〔Stewart, John Q., "Demographic Gravitation: Evidence and Applications," ''Sociometry'', Vol. 11, No. 1/2. (February - May 1948), pp. 31-58. ()〕 It is an attempt to use equations and notions of classical physics - such as gravity - to seek simplified insights and even laws of demographic behaviour for large numbers of human beings. A basic conception within it is that large numbers of people, in a city for example, actually behave as an attractive force for other people to migrate there, hence the notion of demographic gravitation. It has been related〔Reiser, Oliver L. "Technology and Society" in Kostelanetz, Richard (Ed.), ''Beyond Left and Right: Radical Thought for Our Times'' p. 85, William Morrow & Co., New York, 1968. ()〕〔Higgins, Benjamin, and Savoie, David J. "Regional development theories and their application", pp.151-155, Transaction Publishers, New Jersey, 1997. ()〕 to W. J. Reilly's law of retail gravitation,〔Reilly, W.J. “Methods for the Study of Retail Relationships” University of Texas, Bulletin No 2944, November 1929.〕〔Reilly, W.J. "The Law of Retail Gravitation", New York, 1931.〕 George Kingsley Zipf's Demographic Energy,〔Stewart, J.Q. “Demographic Gravitation: Evidence and Application” ''Sociometry'', Vol. XI, February–May 1948, pp 31-58.〕 and to the theory of Trip distribution through gravity models Trip distribution#Gravity model. Writing in the journal ''Sociometry'', Stewart set out an "agenda for social physics." Comparing the microscopic versus macroscopic viewpoints in the methodology of formulating physical laws, he made an analogy with the social sciences:
Stewart proceeded to apply Newtonian formulae of gravitation to that of "the average interrelations of people" on a wide geographic scale, elucidating such notions as "the demographic force of attraction," demographic energy, force, potential and gradient.〔 ==Key equations== The following are some of the key equations (with plain English paraphrases) from his article in sociometry: : (''Demographic Force = (population 1 multiplied by population 2) divided by (distance squared)'') : (''Demographic Energy = (population 1, multiplied by population 2) divided by distance; this is also Zipf's determinant'') : (''Demographic Potential of population at point 1 = population at point 2, divided by distance'') : (''Demographic Potential in general = population divided by distance, in persons per mile'') : (''Demographic Gradient = persons per (i.e. divided by) square mile'') The potential of population at any point is equivalent to the measure of proximity of people at that point (this also has relevance to Georgist economic rent theory Economic rent#Land rent). For comparison, Reilly's retail gravity equilibrium (or Balance/Break Point) is paraphrased as: : (''Population 1 divided by (distance to balance, squared) = Population 2 / (distance to balance, squared)'') 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Demographic gravitation」の詳細全文を読む スポンサード リンク
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