THE STRUCTURE AND DYNAMICS OF CENTRAL PLACE SYSTEMS: A CASE STUDY OF SOUTH-WEST NIGERIA CENTRAL PLACES

Abstract

This study analyses the spatial structure and the underlying processes of central places in South-West Nigeria. It adopts the systemic approach to the problem of spatial structure and spatial dynamics and then utilises concepts of “order by fluctuation and dissipative structure" developed in physics as alternative explanatory paradigm for examining the changing relationships between spatial structure and spatial dynamics. The study operationalised conceptual issues such as, systems analysis and systems of central places human settlement as central places; and, spatial dynamics and spatial structure. It also discussed central place theory [CPT] and Dynamic central place theory [DCPT] as theoretical foundation for the research. The study covered all central places in South-west Nigeria with population figures of 5,000 and above in 1952. However, local government headquarters [1976 local government reforms] that do not meet this criterion were included, being central places to their geo-political units. The spatial structure of the one hundred and thirty six central places so identified between 1900 and 1963 were analysed using population data. Since this variable is discontinuous after 1963, a total of fourty-five central functions were collected for each of the central places for three different periods - 1967, 1976 and 1991. These central functions which covered industrial, commercial and service activities were obtained mainly from secondary sources. The changing distribution pattern of the central places since 1900, is first examined using high order Nearest Neighbour technique, while both qualitative and quantitative changes in the spatial structure are evaluated with certain indices of population growth and concentration. Processes of central place growth are discussed within three dominant historical phases, namely, pre-colonial, colonial and early independence epochs. The study then employed multivariate factor analytical technique to examine and analyse the structural features of the central places in the three time periods - 1967, 1976 and 1991 [important benchmarks in Nigeria's political and economic history] . It further employed the technique of hierarchical cluster analysis to define the functional hierarchy of the central places. Changes in the hierarchical structure of the central places within different classes or orders are analysed using the Markov chain model, which also provides a framework for generalising the spatial processes of the central places. From a detailed analysis of the structure of central places, the study identifies pertinent spatial processes that govern spatial structure of development in the region. These spatial processes are related to the observed spatial structure of the central places by an explanatory/predictive canonical model. Changes in the relationships are also examined while processes that govern the spatial structure are quantified. The results of the higher order nearest neigbour analysis shows no statistically significant changes in the location pattern of the central places. However, there is a marked deviation of the distribution pattern of the central places from theoretical postulation of regularity. Factors of socioeconomic and political culture of the Yoruba race within prevailing physiographic context are noted to be fundamental to the observed distributional pattern of the central places. Furthermore, observed variations in the relative sizes and growth structure of the central places from earliest times to date are understandable within broad geographical cum historical context of regional central places. Essentially, it is the nature and changing role of the centers as historical settlements and traditional centers of trade, administration and cultural activities that are fundamental. Furthermore, the factor analytical technique shows that the regional central places possess three basic structural features which are; Industrial development; Education and commerce; and, Social or basic services. Based on the identified dimensions, the hierarchical cluster analysis reveals that five classes or orders of centers are distinguishable in the three periods. It is observed that changes in the hierarchy of the central places can be described by Markov chain model. The results of the model show that higher order centres are more stable in the hierarchy, and that the probability of lower order centres moving into higher orders decreases with time. However an equilibrium distribution of centres in the hierarchy will be reached by the year 2026 A.D. The results of the canonical correlation model of the relationship between spatial structure and spatial processes show that the observed variations in the spatial structure of the S.W. Nigeria central places are due mainly to changing but differing political functions of the central places and their accessibility seen in the strategic location of a center as either Port city, or along important road or railway network or air accessibility. This study provides useful information on the trend and character of the regional space economy and, the types and relative strength of the underlying spatial processes. It is suggested that research into spatial dynamics of regional economic structure, should begin with an examination of the spatio-temporal structure of the system of interest, rather than invoking constant universal processes to be related to a spatial structure. The significant relationship between spatial structure and processes produced by the canonical correlation in this study shows that relevant spatial processes could emerge from a careful analyses of a spatial structure. The study further shows that while systems analysis provides an adequate framework for conceptualizing the web of interrelationships in a spatio-temporal organisation of cities, the unraveling of these relationships remains a major challenge to the formulation of theories and development of models of temporal and spatial processes.