Checking and analysis of spatial organization and structure of urban habitations of Guilan province

Population data is easily accessible and shows the relationship between city size and other socio-economic factors in the city indirectly, so many geographers using this type of data to gain an understanding of the structure of the cities network and distribution of the people in the different levels of urban hierarchy. In fact, urban hierarchy is the best way of space organization in respect to population distribution and function in the area. But the most important part of urban hierarchy is the relationship between neighbor habitats. The dynamics of urban systems could be seen from the traffic of goods, services, thoughts and population among city centers and rural areas. A structured urban hierarchy results in equal distribution of goods and services and facilities in the region. In third world countries, there is an unbalance population distribution in the urban hierarchy. Iran as a third world country is under pressure from recent rapid urbanization and subjected to changes in the urban hierarchy resulted to an inequality in its city network structure.
Literature review: Cities could be known as a reflection of many social and economic processes thorough time that their formations, relations and interactions create a complicated system, so urban systems are known as main part of spatial structure (Rostaii, 1998: 1). Distribution of cities in urban network is called urban hierarchy (Farid, 2000: 396). There is two main interests in the study of urban hierarchy; one based on population size, economic structure and relation between cities and one based on the flow of data and information. In fact, urban hierarchy is the spatial vision of all of the small and big habitats in the national economy. In developed countries, due to existence of many functions and activities in every city and an equality in distribution of economic opportunities, the urban network is like galaxy.
The economic and political concentration processes in Iran in recent decades, led to the phenomenon of prime city in the country and the dominance of Tehran over other cities in urban network. On the other hand in provinces, central cities acted as a prime city in the area and the second city usually is far from it in respect to population and function. These shows the concentration of investment and function in large cities that absorbs resources from peripheral cities to large cities and metropolises. Guialn province like other provinces in the country experienced this situation. In this province, Rasht due to its politic and economic situation, its location in the region and due to existence of required economic infrastructures for production especially in industry and service sectors, is considered as the main pole in the region. This caused the population migration to the city, even from other provinces and led that many other parts of the region remain undeveloped. So the main goal of this study is to analyze the urban hierarchy in Guilan province between 1966 – 2011.The method of the study is analytic and descriptive based on some of the urban and regional planning models.
The results shows that the urban hierarchy in the province is unequal in the situation is getting worse. in this study using different models like differential levels, entropy coefficient, rank size rule, prime city factor, the Jefferson factor, the Kingsburge factor, Mahta factor and Momow factor, it is shown that the urban hierarchy in the province is unequal and in the recent 50 years, the urban network have faced prime city phenomenon. The results of the entropy model shows that the urban hierarchy is facing inequality. According to differential model, more than 94 percent on the cities in the province are in the first group with a low population and only 43 percent of people live in these cities. On the other hand Rasht with a population about 43 percent of the province, is the pole in the seventh group. Also based on rank size rule, it is concluded that the urban hierarchy in the province is very different from the rule. The result showed the dominance of the prime city and the increase of the small size cities and absence of middle size cities. The results of the analysis with the Jefferson factor showed the spatial inequality and the huge difference between prime city (Rasht) and second city (Bandar-e-Anzali). Also the results of the analysis with the Kingsburge factor, shows in inequality in population distribution in Guilan province. Based on the results of four city of Mahta, it can be inferred that the Guilan province faces prime city phenomenon and in the last decade faced super prime city. Analysis of the prime city phenomenon based on Momow factor was similar to other results and showed the existence of the prime city phenomenon in the Guilan province.