Luc-Normand Tellier

From the Weber Problem to a ‘Topodynamic’ Approach to Locational Systems

In any given space, a sequence of interdependent Weber problems of a certain type leads to a pattern of locations which can be mathematically characterized. Conversely, the observed evolution of a given locational system corresponds to certain characteristics of an analogous Weberian locational system. Determining such characteristics leads to the simulating and forecasting of the evolution of the observed locational system. A model corresponding to such a ‘topodynamic’ approach is presented and an application is made. Three different effects are integrated into the model: an interdependency effect which determines the polarization level; an ‘attraction — repulsion’ effect which determines the center — periphery equilibrium; and a distance deterrence effect which determines the diffusion process and the inertia level.

PROJECTING THE TOPODYNAMIC EVOLUTION OF THE WEST-AFRICAN URBAN SYSTEM: Is West Africa Heading for an “Urbexplosion” or an “Urbimplosion”?

ABSTRACT In this paper are presented some results of a topodynamic analysis of the evolution of the West African urban system. Topdynamic projections are studied in order to characterize the most basic trends of the system. From pure description and forecasting the paper moves to launching a discussion on the economic implications of the observed and projected trends in population distribution. Is the urban boom tantamount to an economic boom or is it a smoke screen hiding a further marginalization of the West African economy on the world stage?

Further Understanding Spatial Inertia: A Reply to Plastria and Rosing

Our position with respect to Plastria and Rosings comments isqualified. Some of their comments are irrelevant because they attack a general statement that is not included in Tellier and Vertefeuilles paper (1995). Portions of their comments on the mathematical framework are relevant and have some implication for the validity of the mathematical relations proposed. A new analysis of the local behavior of the Weberian optimum is presented and its probabilistic interpretation is emphasized. On the basis of this analysis and ofempirical observation, we maintain that Tellier and Vertefeuilles paper was genericallycorrect with regard to spatial inertia.