The concept of hierarchy involves ranking towns or shopping centres into grades or ranks according to size or function. It is useful to be able to do this, to talk of village, town and city, whether or not there is an underpinning of theory to justify it. The idea of the hierarchy requires there to be fairly clear differences between different ranks so that it is not too difﬁcult to tell what type of animal we are looking at. The alternative to the hierarchy is the continuum where the settlements rise continuously in size of population. Here the concept is of a continuous line from a large number of small settlements to a small number of large cities, with the level of service provision rising pro rata or linearly. The hierarchy in contrast requires there to be breaks in this continuum.