Gravity model of migration
- Gravity model of migration
The Gravity model of migration, which is derived from Newton's law of gravity, is used to predict the degree of interaction between two places. Newton's law states that: "Any two bodies attract one another with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them."
When used geographically, the words 'bodies' and 'masses' are replaced by 'towns' and populations respectively. The Gravity Model in migration is therefore based upon the idea that as the size of one or both of the towns increases, there will also be an increase in movement between them. The further apart the two towns are, however, the movement between them will be less. This phenomenon is known as distance decay.
The Gravity Model can be used to estimate:
* Traffic Flows
* Migration between two areas
* The number of people likely to use one central place
The Gravity Model can also be used to determine the sphere of influence of each central place by estimating where the breaking point between the two settlements will be. An example of this is the point at which customers find it preferable, because of distance, time and expense considerations, to travel to one center rather than the other.
The gravity model was expanded by William J. Reilly in 1931 into Reilly's law of retail gravitation to calculate the breaking point between two places where customers will be drawn to one or another of two competing commercial centers.
Opponents of the gravity model explain that it can not be confirmed scientifically, that it's only based on observation. They also state that the gravity model is an unfair method of predicting movement because its biased toward historic ties and toward the largest population centers. Thus, it can be used to perpetuate the status quo.
Wikimedia Foundation.
2010.
Look at other dictionaries:
Gravity model — Gravity models are used in various social sciences to predict and describe certain behaviors that mimic gravitational interaction as described in Isaac Newton s law of gravity. Generally, the social science models contain some elements of mass… … Wikipedia
Human migration — Net migration rates for 2008: positive (blue), negative (orange), stable (green), and no data (gray) … Wikipedia
Global climate model — AGCM redirects here. For Italian competition regulator, see Autorità Garante della Concorrenza e del Mercato. Climate models are systems of differential equations based on the basic laws of physics, fluid motion, and chemistry. To “run” a model,… … Wikipedia
Indo-Aryan migration — For other uses, see Indo Aryan migration (disambiguation). Indo European topics Indo European languages (list) Albanian · Armenian · Baltic Celtic · Germanic · Greek Indo Iranian … Wikipedia
Nice model — The Nice model (pronounced /ˈniːs/, like niece) is a scenario for the dynamical evolution of the Solar System. It is named for the location of the Observatoire de la Côte d Azur, where it was initially developed, in Nice, France.[1][2] It… … Wikipedia
Diel vertical migration — Diel vertical migration, also known as diurnal vertical migration, is a pattern of movement that some organisms living in the ocean and in lakes undertake each day. Usually organisms move up to the epipelagic zone at night and return to the… … Wikipedia
Planetary migration — occurs when a planet or other stellar satellite interacts with a disk of gas or planetesimals, resulting in the alteration of the satellite s orbital parameters, especially its semi major axis. The generally accepted theory of planet formation… … Wikipedia
Land use forecasting — undertakes to project the distribution and intensity of trip generating activities in the urban area. In practice, land use models are demand driven, using as inputs the aggregate information on growth produced by an aggregate economic… … Wikipedia
Buffer Theory — In the late 1950s a number of European countries (most notably West Germany and France) decided on a migration policy know as the Buffer theory. Owing to rapid economic recovery in the post WWII period (aided by the American Marshall aid program) … Wikipedia
geography — /jee og reuh fee/, n., pl. geographies. 1. the science dealing with the areal differentiation of the earth s surface, as shown in the character, arrangement, and interrelations over the world of such elements as climate, elevation, soil,… … Universalium
