The changes of parameters in gravity models

Auteurs :
LUOMA, M.
MIKKONEN, K.

Description :
The aim of the research was to develop a gravity model which would explain dependencies between model parameters on the one hand, especially the distance-decay parameter and the centrality of centres on the other hand. Time dependencies were also the focus of attention. The visiting frequencies to a centre performed by a household during one year were used as a measure of field force. The data was based on two consumer surveys which were carried out among the people of the Administrative Province of Vaasa, Finland in 1971 and 1980. In the model building, we supposed that the visiting frequencies follow some stochastic process. The Poisson process proved to be the most appropriate choice. On the basis of the Poisson process an efficient estimation method was developed for the gravity model. Finally a common gravity model was developed by expressing the distance-decay parameter and the multiplier as a function of the mass. The Iteratively Reweighted Least Squares-method was used in the estimation of common model parameters for 1971 and 1980. The gravity model thus developed is considered a very useful for the delimitation of spheres of influence and for strategic planning in retail trade.


Type de document :
Article de périodique

Source :
Fennia (Helsinki. 1889), issn : 0015-0010, 1989, vol. 167, n°. 1, p. 1-17, Références bibliographiques : 1 p.

Date :
1989

Editeur :
Pays édition : Finlande, Helsinki, Societas Geographica Fenniae