What is the gravity model of spatial interaction?

What do we mean by gravity in spatial interaction models?

The Gravity Model holds that the interaction between two places can be determined by the product of the population of both places, divided by the square of their distance from one another. The primary implication of this model is that distance is not the only determining factor in the interaction between two cities.

What does the gravity model of spatial interaction conclude?

One of the most significant aspects of gravity models (or as they are now known in geography – spatial interaction models) is that they formally specify the relationship between distance and the likelihood of interaction. Holding all other effects constant in the model [1], as distance increases, interaction decreases.

What are the models of spatial interaction?

Four main frameworks have been postulated for this purpose and in chronological order these are: (a) spatial interaction as social physics; (b) spatial interaction as statistical mechanics; (c) spatial interaction as aspatial information processing; and (d) spatial interaction as spatial information processing.

What is the meaning of gravity model?

A gravity model provides an estimate of the volume of flows of, for example, goods, services, or people between two or more locations. This could be the movement of people between cities or the volume of trade between countries.

What is a gravity model GIS?

GIS Dictionary. gravity model. [geography] A model that assumes that the influence of phenomena or populations on each other varies inversely with the distance between them.

Why is the gravity model important?

The gravity model estimates the pattern of international trade. While the model’s basic form consists of factors that have more to do with geography and spatiality, the gravity model has been used to test hypotheses rooted in purer economic theories of trade as well.

What is an example of gravity model?

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 can be used to measure accessibility to services (e.x., access to health care).

Where is the gravity model used?

The gravity model can also be used to compare the gravitational attraction between two continents, two countries, two states, two counties, or even two neighborhoods within the same city. Some prefer to use the functional distance between cities instead of the actual distance.

How is the gravity model used today?

In the gravity model of human geography, we can use these same variables. Size is measured in population, and distance can be measured using any metric. The idea in the gravity model is the same as in Newton’s law. The larger and closer two places are, the more influence they’ll have on each other.

Why is the gravity model of migration important?

Due to the recent availability of bilateral (i.e. two-way, country to country) migration data, gravity models have become more frequently used in the context of migratory flows. This allows for a better understanding of migration determinants when assessing policy impacts.