Central places

Articles

• Isotropy/anisotropy
  8 September 2010, by Th. St.-J.

  An environment or medium is said to be isotropic if its physical properties are identical in all directions. A «system» will be termed isotropic if its (macroscopic) properties are invariant in relation to a particular direction, and therefore none of these properties is directionally dependent. Should one of its properties be directional, the system is not isotropic, but anisotropic. A physical magnitude can also be said to be anisotropic or isotropic according to whether or not it is (...)

• Aggregation
  13 October 2004, by D. P.

  Process of grouping of persons or activities together in a same place or in an area of limited size. Settlement nodes develop through aggregation of migrants, cities through aggregation of houses or even of urban municipalities when speaking about agglomerations. Services and facilities of a same range aggregate to form a same functional level: it is one of the fundamental assumptions of Christaller’s central places theory. Aggregation processes suppose that similarities or (...)

• Theories of spatial analysis
  12 January 2005, by D. P.

  The general theoretical position of spatial analysis consists in proposing a partial explanation as well as prediction possibilities about the state and probable evolution of geographical objects / entities, on basis of knowledge of their situation with respect to other geographical objects.
  There exists not yet any general theory of geographical space that could be a theory of concentrations, of spacing, of spatial structures and of evolution of spatial systems, relying on knowledge of (...)

• Christaller (model of)
  6 October 2004, by D. P.

  Model elaborated by the German geographer Walter Christaller in 1933, derived from the central places theory which gives account of the size, spacing and number of cities. The model describes the hierarchical organisation of a network of cities according to the level of services they provide, and their regular spatial disposition on the vertices of equilateral triangles or at the centre of hexagons.
  An undifferentiated geographical space is imagined, a homogeneous plain, where density of (...)

• Central places theory
  13 October 2004, by D. P.

  The central places theory was conceived, primarily by W. Christaller and A. Lösch, in order to explain size and number of cities and their spacing in a territory. It relies on a definition of city that considers it essentially as a distribution centre of goods and services to a scattered population, and on optimisation principles (which take transport costs into account). This theory stands on the limit between geography and spatial economy, and may be claimed by both disciplines. The (...)

• Centrality
  6 October 2004, by D. P.

  Concept analogous to that of market in economy; supply and demand for services meet and exchange in places privileged for their accessibility, which are central places.
  1. In a network, it characterises the position of nodes in terms of accessibility (see centrality index), the centre being the place endowed with maximal accessibility;
  2. For a city, it measures the importance of urban centres in function of the importance of services they provide to customers from outside, i.e. which do (...)

• Theories of spatial analysis
  3 December 2004, by D. P.

  The general theoretical position of spatial analysis consists in proposing a partial explanation as well as prediction possibilities about the state and probable evolution of geographical objects / entities, on basis of knowledge of their situation with respect to other geographical objects.
  There exists not yet any general theory of geographical space that could be a theory of concentrations, of spacing, of spatial structures and of evolution of spatial systems, relying on knowledge of (...)

• Hierarchy
  6 October 2004, by D. P.

  The notion of hierarchy is used with two distinct meanings. It is a social, political or administrative organisation in levels where each element belonging to a level is strictly subordinated to an element of upper level. The higher it is gone in the order of power or domination, the fewer elements are comprised in each level: hierarchy implies a pyramidal organisation. The benefit of such form of organisation is to allow making information circulate or imposing decisions while reducing (...)

• Area of influence (zone of influence)
  31 August 2004, by D. P.

  Area polarised by a centre, for a set of relations (influence area of a city) or a category of relations (area of cultural or commercial influence, trading area). The notion of influence is difficult to specify. It is measured on basis of frequencies (or probabilities) of travels made by inhabitants of the periphery toward the centre when using services it provides. Areas of influence (e.g. map drawn by G. Chabot in 1952 for the French cities) have almost circular shapes because probability (...)

• Distance
  6 October 2004, by D. P.

  Interval to cover in order to go from one place to another, distance has a meaning of separation, its covering requires effort, expense of energy. The mathematical definition of distance is restrictive: a measure of gap between objects is a distance if it is symmetrical, if it is not negative, if it is null only when two objects merge, and if it verifies triangular inequality. A space endowed with distance in the mathematical meaning is a metric space. Observed or cognitive geographical (...)