Spatial structure of urban settlement systems : stability versus changeability

Postulates of W. Christallers central-place theory are discussed with an introduction of a new sixth postulats. Under consideration are specific cases of settlement systems which can not be described by the apparatus of the classical central-place theory. It is shown that besides external causes responsable for the deformation of Christaller grid (anisotropy of the territory, etc.) there are some inner, immanent causes of it which have spontaneous nature. The paper formulates basics of the relativist version of the central-place theory, introduces notions of "the degree of stability of urban settlement systems" and “isostatic equilibrium" (as an attractor). It presents the results of analysis of the degree of stabilite of settlement systems of Estonia, Armenia, Georgia, and Central Russia. It is substantiated that it is possible to create a theory of the Great Unification by applying the synthetic approach to both the relativist central-place theory and phasic conceptions of spatial development