John William Aitchison

Articles

Cluster analysis and large data sets: a case study of farming systems in France

John William Aitchison

Geographia Polonica (1989) vol. 57, pp. 13-22 | Full text

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Abstract:

With the increasing availability of large, spatially-indexed data banks and the emergence of sophisticated geo-processing systems, agricultural geographers are now in a position to undertake much more detailed and wide-ranging investigations into the typological and regional structure of farming systems. These technological develop-ments also allow a more experimental and critical stance to be adopted in studies of a taxonomic (classificatory) nature. This is important since classification is essentially an exploratory process — a search for meaningful or revealing patterns of order within complex multivariate data sets. It is not a search for single solutions that can be regarded as "definitive" or "true". Typologies and regionalizations can be effected in many different ways, and it behoves would be taxonomists to test and evaluate a range of classificatory models, and to justify the categorizations that are eventually selected for subsequent interpretation. Needless to say, the fact that it is now a relatively simple matter to generate maps and plots of classified units aids this process of experimen-tation considerably, for from a geographer's point of view it is often the meaningfulness of the resultant spatial distributions that is of paramount diagnostic importance. It is not possible here to examine these various issues in great detail; the more limited aim is to consider the general problem of classifying large sets of agricultural data. In so doing, particular emphasis will be placed on "iterative partitioning" methods of cluster analysis.

Keywords:

John William Aitchison, Department of Geography, University College of Wales, Aberystwyth, UK

Model types of world agriculture: Problems of definition and case identification

John William Aitchison

Geographia Polonica (1983) vol. 46, pp. 175-186 | Full text

Further information

Abstract:

In his paper to the 1974 meeting cf the Commissicn cn Agricultural Typology Kostrowicki1 isolated a series of twenty-two variates deemed to be of diagnostic significance for the classification, and subsequent regionalization, cf world agricul-tural landscapes. Applying these defining characteristics to a laige sample cf ca-ses, culled from a miscellany of sources, also led him to propose a two-tier typolo-gy composed of fifty-three agricultural classes. Although there is no suggestion that these classes are exhaustive, or for that matter inviolable, it is clear that they are considered sufficiently distinctive and comprehensive to serve as archetypal templa-tes, against which newly derived case data can be matched for purposes cf classi-fication. It is to this matching or identification process and the problems associated with it that the present paper addresses itself.

Keywords:

John William Aitchison, Department of Geography, University College of Wales, Aberystwyth, UK