Christaller, Walter (1893–1969)

Before the German geographer Walter Christaller's central place theory (1933), urban places were viewed in isolation from one another, as unique single entities, differentiated by their position in a hierarchy based on population size. Christaller's dissertation, Die zentralen Orte in Süddeutschland, broke from this prevailing view. Instead, Christaller demonstrated the spatial interdependence between places. Interdependence arose because of location relative to other places in the system of places. A place's population size and trade with other places were determined by its location.

Christaller's central place theory concluded that a hierarchy of places would arise as the system of places tended toward spatial equilibrium. Within the hierarchy of places, higher-order places would offer goods and services that required greater numbers of people distributed over larger trade areas for their support. Successively lower-order places would offer goods and services that required fewer people to sustain the activity. Lower-order places with their smaller trade areas are embedded among fewer higher-order places and their larger areas of geographic dominance.

Christaller inductively derived propositions about the population size of places, number of places, and locational distribution of places. He described five sizes of communities:

• 1.
  Hamlet
• 2.
  Village
• 3.
  Town
• 4.
  City
• 5.
  Regional capital

Christaller was the first to propose a geographically determined hierarchy of places, conforming to specific geometric principles. His hypothetical landscape was composed of trade areas in the shape of hexagons. Hexagons are the most compact of packable shapes. Christaller's reasoning was that depending on the initial assumptions of the model or characteristics of the landscape, development of urban places would occur on the apexes, arcs, or interior of the hexagonal trade area boundaries—the market, transportation, or administration system, respectively. Christaller described the conditions that would bring about the particular geometry of places. In the absence of a transportation network, lower-order places would grow at the location of the apexes, exactly one third of the way between three next-higher-order places. If the landscape included a transportation network that minimized fixed costs and connected the highest-order places, then locational advantage would shift to the arcs of the hexagonal trade areas, with the growth of lower-order places occurring midway between a pair of next-higher-order places. Trade results between the places, and the revenues of a place depend on the geometry that characterizes the system of places. Christaller recognized the importance of internalizing externalities within a hierarchy of administrative zones.

There are a greater number of lower-order places, and they are closer together than higherorder places. Lower-order places depend on higher-order places for the provision of goods and services not available locally, and higher-order places depend on lower-order places to provide [Page 410]demand sufficient for the provision of those goods and services unique to the higher-order places. Because of trade, all places are interdependent in space. The growth opportunities of a place are given by its location relative to other places. Christaller's rigid geometry of place location produces an efficient system for trade, growth, and development.

The German economist August Lösch (1906–1945) generalized Christaller's central place theory in his 1939 book published in German, The Economics of Location. Instead of Christaller's distribution of places and their functional order that maximized profits, Lösch's system was based on minimizing the cost of consumers’ accessing needed goods and services. Lösch provided a deductive, more formal economic approach to the growth and spatial distribution of urban places.

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