Jim Walsh

Information Theory: Some Concepts and Measures

The concepts of entropy and of information are increasingly used in spatial analysis. This paper analyses these ideas in order to show how measures of spatial distributions may be constructed from them. First, the information content of messages is examined and related to the notion of uncertainty. Then three information measures, due to Shannon, Brillouin, and Good, are derived and shown to be appropriate in analysing different spatial problems; in particular, the Shannon and Brillouin measures are extensively compared and the effects of sample size on them are investigated. The paper also develops appropriate multivariate analogues of the information measures. Finally, some comments are made on the relations between the concepts of entropy, information, and order.

Adoption and Diffusion Processes in the Mechanisation of Irish Agriculture

Mechanisation is an important component of the modernisation of agricultural production. It involves the adoption and diffusion of many innovations. The processes which affect the adoption and spatial diffusion of innovations in Irish agriculture have been subjected to very little systematic analysis. This paper traces the introduction and spread of tractors in both the Republic of Ireland and Northern Ireland from the 1920s to the present. A strong hierarchical effect is evident in the adoption and diffusion pattern which extends westwards from some key clusters of early adopters in the east and south. The distributions of farm sizes, tillage, and hired agricultural labourers, are suggested as important influences on the spatial pattern. Also of importance were the locations of distributors and the networks established by the main suppliers, though this factor requires more research.

AN ENTROPY MAXIMISING ANALYSIS OF JOURNEY-TO-WORK PATTERNS IN COUNTY LIMERICK

Entropy maximising models have become increasingly popular among geographers and regional scientists over the last decade. Yet there remains a considerable amount of confusion about the rationale for these models. This paper attempts to clarify the main issues and to illustrate the potential of the entropy maximising procedure in the area of journey-to-work modelling. Calibration methods and goodness of fit statistics are discussed. The latter half of the paper analyses recent journey-to-work patterns in County Limerick by the entropy maximising method and concludes by suggesting further applications of the model and areas of research.

The governance of local development: An assessment of organizational capacity in North West Europe

Many of Europe’s regions and localities have traditionally relied for their development on central government policy intervention and large-scale enterprise (Stohr, 1990). However, over the past 25 years they have adjusted these preferences by more fully embracing local action. Today, the theory and practice of local development emphasize its potential to identify and harness a wide variety of resources in ways that are often more effective and efficient than top-down initiatives acting alone. This approach requires appropriate governance arrangements that are strongly supportive, not least politically, of local activity. It requires the formation and operation of local level alliances by stakeholders who can think and act strategically within organizational structures whose missions have been shaped by those whom local development programmes are intended to benefit. And of course, it is vital that the scope of local development is defined as a multi-dimensional set of activities that recognize the interdependence not just of social, economic, cultural and environmental measures, but also the very real connectedness between people and place. Spatial development approaches to local development are, therefore, an important element of any coherent local development framework. The latter point is especially important in that strategic spatial planning at multiple scales is now very much in vogue across Europe. Albrechts et al. (2003) have argued that ‘strategic frameworks and visions for territorial development, with an emphasis on place qualities and the spatial impacts and integration of investments, complement and provide a context for specific development projects’ (p. 113). One of the important observations that they make is that this strategic focus on spatial development has the capacity to shift governance cultures and in

AN EMPIRICAL ASSESSMENT OF THE ENTROPY MAXIMISING FAMILY OF INTERACTION MODELS

The parameters, and consequently the performance level, of statistical models of spatial interaction are particularly dependent on the spatial organisation framework which is used to organise interaction data and the way in which the costs of interaction arc measured. This paper provides an empirical assessment of the influence of these factors on the performance levels of the entropy maximising family of interaction models, the members of which differ according to the extent of their data requirements. The principal results which emerge are as follows. The level of model performance generally improves as the number of constraints increases. However, the need for a constraint on the average cost of an interaction appears to be relevant at only one level of spatial organisation. The effect of increasing the number of zones in the spatial organisation framework from eight to twenty-two is only a marginal deterioration in the level of model performance. The use of straight line distances in the calibration o...