Leslie Curry

A spatial analysis of gravity flows

Curry L. (1972) A spatial analysis of gravity flows, Reg. Studies 6, 131–147. Since Wilson gave theoretical substance to the gravity model, it is possible to treat it analytically. His derivation is discussed and calibration problems examined. In particular, the general constraints on the maximum entropy solution he obtains can be particularized. Here the association between the spatial distribution of jobs and homes is investigated using a spatial regression operator which is interpreted as the impulse response function of a second order difference equation. By using Z transforms, the regression and gravity operators are applied in paralle. Feedback from the resulting trip pattern allows the job-home relation to be changed sequentially. Measures of spatial entropy and joint information are introduced and related to travel entropy.

Those gravity parameters again

Curry L., Griffith D. A. and Sheppard E. S. (1975) Those gravity parameters again, Reg. Studies 9, 289–296. The arguments presented in a recent paper by Cliff et al. (1974) as regards the relation between gravity parameters and map pattern are reassessed. First, the experimental simulation model designed to support their assertions is examined and found wanting in several fundamental aspects. Second, their statistical argument is evaluated, and it is concluded that when attention is concentrated on specification and interpretation of the parameters rather than on bias in their estimates, then the gravity specification does indeed confound spatial interaction and spatial structure.

Inefficiencies in the geographical operation of labour markets

Curry L. (1985) Inefficiencies in the geographical operation of labour markets, Reg. Studies 19, 203–215. After postulating an efficient overall competitive spatial price equilibrium in labour markets, the real world map of wages and labour flows is introduced as an inefficient form of this configuration because of opportunities not being exploited and wages not being ‘correct’ due to ignorance. Since these markets operate via local information and income flows the employment status of an individual affects that of his neighbours. Depending on the intensity of labour demand and the coupling strength between contiguous pairs on a regular lattice, the economy can break up into polarized patches of different economic climates. Singularities now develop and previously monotonic functions develop flat parts.

Inefficiency and Instability of Trade Patterns

The motivation of this paper is a probing of the range of validity of competitive pricing. In the presence of externalities pricing systems are inefficient allocators. Sheppard and Curry (1982) have discussed conditions under which spatial price equilibrium will not distribute a commodity from suppliers to markets efficiently. However, the aim of this paper is to go further, to show that the world trade system is inefficient because of an inherent feature of market forces. In particular, the inefficiencies of large scale inflation and unemployment have existed for a number of years, a regime that seems to have been inaugurated with the shock of the oil prices increase.

Trade as Spatial Interaction, and Central Places

We have lived for so long under the naive morphological studies of commercial geography and the spaceless structural ideas of economics that it requires a real effort to envisage a genuine geographical study of trade. Written by economists for economists, the theory of trade rarely provides answers to specifically geographical questions: in particular, it has not provided any results concerning spatial arrangement. While criticism is easy (Curry, 1985a) it is much more difficult to provide the right sort of analytical apparatus.