Rank-Size Rule

The rank-size rule is a mathematical description of the sizes of cities within a given urban hierarchy. It states that the rank of a city with size S relative to the largest city in that hierarchy is proportional to some negative power. It was first proposed by George Kingsley Zipf in 1949. The negative power should be close to 1 in absolute value, which implies that the second largest city is half the size of the largest, the third largest city is one-third the size of the largest, and so on. In cases where this power is greater than 1, it suggests that the second largest city is more than half the size of the largest city, the third largest city is more than one-third ...