ZIPF'S LAW IN THE CASE OF MOROCCAN CITIES

Abstract

type="main" xml:lang="en"> In this paper, we explore the validity of rank-size rule in the Moroccan urban system. We use data from the 1982, 1994, and 2004 censuses. Three thresholds are considered to truncate the data: 5000, 50000, and 100000 residents. Power law states that the rank (r) of a city is proportional to a power of its size (S r ), that is, r S-super-•-super-α. The ordinary least squares (OLS) method is used to estimate α. Using OLS method without Gabaix-Ibragimov correction (GIC) provides evidence of the validity of Zipf's law for cities of more than 100 000 dwellers.When the GIC is used, it appears that the zipfian distribution (α = -1) is also valid for cities of more than 50000 inhabitants. Over the period 1982–2004, it seems likely that intermediate cities grew more rapidly than other cities. This may lead to a more balanced distribution of the Moroccan urban system.