Christaller, W.

Walter Christaller (Figure 1), a German geographer and one of the founding fathers of the 'central place theory', was born on 21 April 1893 in Berneck in the Black Forest, and died on 9 March 1969 in Ko?nigstein in Taunus (Hesse), at the age of 75. His mother belonged to a cultured middle class family of Darmstadt and in her mature years she was a successful novelist. His father, relatively poor, was a clergyman and theologian, but he became involved in doctrinal conflicts and as a result of his hostility to the church and of his partial deafness, he lost his office. During his childhood, Walter Christaller was fascinated by maps; he was spending hours looking at them, taking imaginary journeys, and marking lines between cities close to each other, forming networks and triangles. A nagging question emerged in his mind at that time: why is it that towns were so regularly spaced along the routes? Why did small towns follow large ones, in apparently regular progression? Years had to pass before he answered these questions to his own satisfaction.

His first studies – undertaken beforeWorldWar I – were in philosophy and political economics at the universities of Heidelberg and Munich, rather than in geography. During the war he became a soldier and, wounded several times, later returned home. These experiences no doubt encouraged a strong interest in socialist ideas which remained with him throughout his life, although now and again he denied and sometimes modified them. During the 1920s, he experienced different jobs – miner, construction worker, newspaper article writer – but the fact that none of these jobs lasted for a long time created personal problems for him because, married in 1921, he was faced with raising three children. Christaller and his wife were divorced in 1928 with an amicable settlement, which allowed him to have good relationships with his three children; in fact, the older daughter recalled later on that during her childhood she drew hexagons for him. During those years Christaller did not pursue geography except for designing a list of code numbers of German towns. He called that activity a hobby, but it was indicative of his mathematical theoretical mind.

In the 1930s, Christaller continued his studies at the University of Erlangen (Bavaria), under the influence of Robert Gradmann, who had led the foundation of a location theory of cities. At that time, Christaller was able to reply to his childhood questions, by creating his so well known urban hierarchy model, presented for the first time in his doctoral degree in political economics earned in 1932. In that year, he left Germany for a short period because of Adolf Hitler's election and Christaller's linkage to the social democratic party. His PhD thesis Die Zentralen Orte in Su?ddeutschland was published in 1933 after his return to Germany. This work was destined to be a landmark in his carrier, a success throughout the world, in more recent time translated into English and into Italian. In 1937–38 he finished a dissertation thesis (Habilitation) on 'Rural settlement in Germany and their relation to community administration', which introduced him in the scientific world as a spatial planner.

Before his studies, no theory had ever tried (1) to interpret regularities in the structure of urban settlements and (2) to give a sound economic explanations to these regularities.

Walter Christaller was able to explain the existence of an 'urban hierarchy', and in particular the size and frequency of urban centers at every level in the hierarchy – and therefore the market area of each of them – and the distance between a particular city and those at the levels immediately below or above it – and therefore the geographical distribution of all the urban centers.

Together with the economist August Lo?sch, Walter Christaller was hence the first to formulate a model able to demonstrate the existence of an urban hierarchy in which each city of a certain size performs a specific function. Moreover, the model is able to furnish rules with which to identify the number of centers of a certain order, the size of each market area of each center, the distances among centers of the same order, and therefore their geographical distribution. Christaller's model is based on the assumption that an urban center exists where there are goods and services to be traded. This central 'place' (hence the name 'central place theory' given to the literature that Christaller's model inspired) must produce or supply goods or services to a population spatially dispersed across a uniform and isotropic surrounding territory. The aim of the model is to show how products and services (especially tertiary functions) come to be territorially organized in an urban hierarchy.

In 1940, Walter Christaller joined the Nazi party, eager to apply his central place ideas, and blind to the political misuse being made of them. He worked at that time for the Reichskommisariat fu?r die Festigung deutsches Volkstums, created in 1939 under the direct control of Himmler. Christaller's job was to plan and classify East German and polish occupied cities of that time on the basis of his theory.

After the fall of the Third Reich, Walter Christaller joined the communist party with the hope that an authoritarian government ''would have used its power to relocalize the cities destroyed during the war on the basis of the optimal framework suggested by the central place theory'' (1949), and in 1951–52 became its deputy in the local council of Darmstadt, the city where he decided to live after the war, thanks to the availability of his mother's house. Because of cooperation in a communist study group on agricultural problems in both East and West Germany, he was charged with espionage, but after some years of legal proceedings all charges were dismissed.

Christaller worked in a field that was exploited politically to a high degree, nevertheless his theory became known very late, and appreciated first of all outside the geography's world. In 1941, thanks to Edward Ullman, Christaller's ideas were introduced in the US under the title 'A theory of location of cities'. In the course of time, Christaller's theory had made an impact throughout the world.

Only in his seventies, Christaller began to receive honors, first from abroad. He was given the outstanding Achievement Award of the Association of American Geographers in 1964, and in 1968 he received honorary doctorates from the University of Lund (Sweden) and of Bochum (Germany). In 2003 he received the posthumous title of 'The century's inventor' in the American journal National Geographic.