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 ...