Compare methods

	Lowry Land-Use Transport Model	Gravity Model of Migration
Field	Human Geography	Human Geography
Family	Process / pipeline	Regression model
Year of origin	1964	1946
Originator	Ira S. Lowry	George Kingsley Zipf (formalized); analogy to Newton's law of gravitation
Type	Spatial-interaction-based land-use and activity allocation model of a metropolitan area	Spatial-interaction regression model for migration flows
Seminal source	Lowry, I. S. (1964). A Model of Metropolis (RM-4035-RC). RAND Corporation, Santa Monica, CA.	Zipf, G. K. (1946). The P1 P2 / D hypothesis: On the intercity movement of persons. American Sociological Review, 11(6), 677–686.
Aliases	Lowry Model, Model of Metropolis, Lowry-Garin Model, Land-Use Transport Interaction Model	Migration Gravity Model, Demographic Gravity Model, Zipf P1P2/D Model, Gravity Model of Spatial Interaction (Migration)
Related	4	4
Summary	The Lowry model is the foundational operational model of urban land use, allocating where people live and where services locate around a given pattern of basic employment using spatial-interaction (gravity) distribution. Devised by Ira S. Lowry at the RAND Corporation in 1964 as 'A Model of Metropolis', it treats the city as a system in which basic jobs attract resident workers, those residents demand local services, and the resulting service jobs attract still more residents — a chain solved by iteration until the whole system balances. It launched the entire field of land-use and transport interaction modelling.	The gravity model of migration explains the volume of movement between two places as proportional to the product of their populations (masses) and inversely proportional to the distance separating them, by direct analogy to Newton's law of universal gravitation. Formalized for intercity movement by George Kingsley Zipf in 1946 and embedded in regional science by Walter Isard, it is the workhorse model of human geography for predicting migration, commuting, and other spatial-interaction flows.