The changes of urban hierarchical system in Lorestan Province from 1355 to 1385

The urbanization expansion, population explosion and population movement have changed very much into the urban systems and patterns of Iran. The aim of this research is to investigate the urban system of Lorestan Province from 1355 to 1390. The methodology is descriptive – analytic one and data gathering is based on the statistics obtained from five periods of census. The statistic community of the research is the urban points of Lorestan Province and the used models are Rank – Size model, Anthropy, Class Difference Limit, and City Primacy Indexes. The research findings indicate that based on the Rank- Size model there has been balance in the urban hierarchical system of the Province from 1355 to 1375 but in 1385 this balance has been a bit disordered. The numbers obtained from Anthropic Coefficient also shows that the urban centralization of the Province has been decreased. The City Primacy Indexes used in this research, on the other hand, show that there exists no City Primacy in the Province; instead, the mediated cities are in great importance in this relevance.