Figure 10.17:
Two of Christaller’s models. (a) The influence of market area on Christaller’s arrangement of central places. If market were the only factor controlling the distribution of central places, this diagram would represent the arrangement of towns and cities. (b) The distribution of central places with the influence of transportation taken into account. If the availability of transportation is the determining factor in the location of central places, their distribution will be different from the distribution that would result if marketing were the determining factor. Note that the second-order central places are pulled away from the apexes of the hexagon to the main transport routes between regional metropolises.
(Source: After Christaller, 1966.)