changes in the urban system in Mazandaran province with emphasis on small towns

The change in urban systems is a continuous process that simultaneously occurs at different levels of space. This article aims to study the evolution of the urban system of Mazandaran province in the last 60 years. The research method is descriptive-analytic and the statistical basis of the data is the results of general population censuses and housing. In this research, Excel data was categorized by demographic data of urban areas and using the rank-size models, the class-adjusted minimum and the pulling coefficient of the urban system of Mazandaran province were analyzed. With Gis, maps of the spatial distribution of urban population were also drawn. The results show that urbanization in Mazandaran is moving along with the whole country, but its acceleration is slower than that of the country. In this period, the number of cities increased 6 times, urban population 12 times, and urbanization increased to 42.2 percent. According to the model, the size of the real and desirable population of cities is seen to be increasing as a surplus population, and as the tendency to balance is evident at high levels of the hierarchical system, there is no such improvement at the lower levels. In the corrected rule of Storges, the degree of difference between classes is increased to 5.6 times, and the number of classes to 10 metropolitan areas has increased, and there is a significant difference between the number of cities and their population in the last floor of this model, which indicates the imbalance and disruption of the situation The hierarchy of the urban system. The results of the model of pulling coefficient show that the small towns and villages in recent decades have been low and negative growth, whose declining role has caused a serious risk of balance in the Mazandaran city system.