system

Articles

• Spatial diffusion
  15 December 2004, by Th. St.-J.

  Diffusion is as well the action as the result of action to spread, or to transmit and propagate in a uniform way. It is thus expressed by all moves which, whatever their driving force, are trying to spread something in a system in an homogeneous way, thus tending to bring it from one equilibrium state to another equilibrium state when, under certain conditions, the system is saturated because its absorbing potential is exhausted. The notion of diffusion, considered from the action (...)

• Spatial mobility
  21 June 2012, by N. C.

  Spatial mobility is an essential component of the way societies organise space. It has been defined in various ways, in reference to different registers of observation and conceptualisation. In its most frequent acceptation, mobility is movement or travel from one «place» to another. This movement can concern people, but also material and immaterial goods, and information. The unit of measurement naturally depends on what is travelling, and can for instance be in terms of numbers of (...)

• 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 (...)

• Agrarian system
  8 November 2013, by L. R.

  This concept identifies any form of agriculture as a “system” of interactions between the establishment and management of a cultivated ecosystem, the agrarian structures (land ownership patterns and landscapes) and the production system (combinations of arable and/or livestock production and the production means implemented in terms of techniques and practices).
  From agrarian structure to farming system
  The older of these two concepts is that of the agrarian structure, used (...)

• Contingency
  18 October 2005, by F.D.-D.

  A philosophical notion that seems particularly useful for geographical reasoning. Lalande goes back to Aristotle for the general meaning of the term: "Est contingent tout ce qui est conçu comme pouvant être ou ne pas être à quelque égard et sous quelque réserve que ce soit [. . .] ( Si bien qu’) un événement futur est contingent si, toutes choses étant ce qu’elles sont, ce futur peut se produire ou ne pas se produire"1 . (The term is opposed in all its meanings to (...)

• Measure
  6 August 2004, by L. S.

  Operation of measure(ment) consists in attributing values to phenomena of interest in the frame of geographical questioning. On the one hand, it is used to characterise attributes of studied objects, and in these cases comes before any processing. On the other hand , it plays a role downstream, to characterise spatial forms, to describe nature and intensity of relations, to qualify similarities, etc. In the first case, measure is apprehended in the phase of acquisition of information and (...)

• City system
  10 May 2016, by D. P.

  A city system; is a group of cities, which, in their evolution, have become interdependent because of the many relationship networks that they have and that interconnect them to a greater extent than other cities located in the environment. It is often the borders of a national territory that constitute the boundaries of a city system, because of the homogeneity of the norms the territory imposes, which contribute to forming some of their relationships. With time, city systems have indeed (...)

• GEOGRAPHICAL CELLULAR AUTOMATON
  8 November 2013, by P. L.

  Cellular automata are as old as the computer. The concept was invented by Von Neumann and Ulam at the end of the 1940s while working at the Los Alamos National Laboratory on the first computers capable of performing the large calculations required in the construction and production of the atomic bomb. Cellular automatons were designed to resolve the problem of the auto-reproduction of living beings. Since then, this notion has been used in numerous fields, including Geography. In the 1950s (...)

• Process
  26 August 2004, by D. P.

  In geography, the notion of process integrates the idea of movement (from Latin pro-cedere: to go forward), of chain of actions or facts. Just as the idea of “dynamics", with which it is sometimes confused, a process makes part of a temporal approach of diachronic type.
  But in a process, the chain of facts is primarily of causal type and secondarily chronological. The succession of phenomena depends on an operative logic that allows integrating them into an interpretable framework. A (...)

• Network
  6 October 2004, by L. C.

  A network is a set of elements that may be material, the infrastructure, and immaterial, electro-magnetic (waves) or informational, which ensure the establishment of relations between different places of a territory and between the entities that are occupying them.
  It comprises not only linear, permanent or temporary, elements which express the existence of relationships and ensure that they are possible, but also nodal elements needed in order to organise flows and to make the system in (...)

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