The Functional Bases of the Central Place Hierarchy

] T is obvious that urban centers differ, each from others. On the intuitive level one notion of difference is that of classes of urban centers. The wealth of descriptive terms available illustrates this notion: hamlet, village, town, city, metropolis, and the like. The present study is concerned with this problem of the differentiation of centers into broad classes. In particular it provides original and urgent evidence that a system of urban center classes exists of the type identified on an intuitive level above. There are several reasons for producing evidence of a system of classes (hereafter termed the hierarchical classsystem) at this time. A considerable body of theory relating to city size, function, and arrangement has accumulated. One of the implications of this theory is that there exists a hierarchical class-system.1 Ample evidence is available that other implications of this theory are valid, namely, that larger centers are functionally more complex than smaller centers, with this increasing functional complexity being accompanied by increasing size of the urban complementary region,2 and that by virtue of the differential provision of central functions there is interdependence between urban centers in the provision of central goods and services.3 On the other hand there has been no satisfactory evidence provided that would suggest that a hierarchical classsystem of centers does indeed exist. Despite many attempts at the assignment of towns to classes or grades4