investigation and analysis of iran urban hierarchy between 1996-2006

â â  the present study attempts to investigate the urban hierarchy in iran between 1996-2006. the research method is content and statistical analysis. the necessity data were collected by documental method. in addition to the analysis and sorting of the data regarding the situation of iranian cities based on different models such as entropy ,ginny coefficients, urban concentration index, and rank –size model. the obtained result shows that in spite of irregular increase in number of village-towns (below 10000 populations) in total of urban system, entropy coefficient has been tended from 0.79 in 1996 to 0.75 in 2006. this trend implicated for high centralization in urban system. ginny coefficient has been increased from 0.76 in 1996 to 0.81 in 2006 that is as symptom for disequilibrium trend in urban system. tehran city is still a primate city in urban system in iran based on the rank-size model. tehran has as many as 3.2 times population as mashhad, which is the second largest city in iran, showing a decrease of about 0.3 since 1996. the urban concentration index based on the first four cities has decreased from 0.61 to 0.59. ultimately, urban hierarchy in iran has very gap compared with zipf's rank-size model and behforooz adjustment model. providing services and strengthening small and middle sized towns coupled with decreasing the growth of mega cities can lead to the optimal distribution of urban hierarchy of cites all over the country.â â