An Analysis of the Developments in the Population Hierarchy System with Emphasis on the Position of the Middle Cities Case study: East Azerbaijan Province.

The term development has been widely used since World War II. This phenomenon is a value, multidimensional and complex category that is the most important discussion of countries today, especially developing countries. Development is a comprehensive process of economic, social, cultural and political activities that aims to continuously improve the lives of the entire population and the fair distribution of resources is one of its main pillars. The main purpose of this article is to analyze the evolution of the demographic hierarchy system. The research is applied and the required data have been collected from the results of the last official population and housing census of the country in 2016. The results show that the western half or semi-developed space of the province includes the north-south axis from Julfa, Marand, Tabriz, Azarshahr to Malekan, which is adjacent to national and inter-regional communication networks and suitable infrastructure networks. Establishment of large industries, small and medium industrial workshops, irrigated and horticultural areas, large villages, densely populated cities, industrial livestock and commercial activities are the features of this area. The eastern half of the province, which has always been deprived due to the natural and mountainous features of the region and the impossibility of central communication with other neighboring provinces, although in some cases the potential for development in them has been more than other regions of the province. Conclusion Establishment of most of the sparsely populated and scattered villages with the dominant economy of traditional herding and animal husbandry, rainfed agriculture and the establishment of sparsely populated cities are the main features of the eastern half of the province. 

Distribution of facilities due to past unprincipled policies in industrial and service mechanisms in the growth pole of the region (Tabriz), and the trend of centralization in one or two large cities as dominant cities and spatial imbalances between regional levels are one of the important issues that have arisen due to various factors, influenced by the mechanisms governing economic, social and political structures. This anomaly and imbalance, with the increasing role of the central government and the low presence of local authorities in the economy due to the nature of its concentration and sectionalism, has increased the problems further, and in this regard, the participation of local people has decreased, and large and small cities have not been seen in an integrated whole. Lack of accurate identification of different dimensions of inequalities and disproportionate executive policies to achieve the aforementioned goals. 

This study is of the practical and theoretical type, the method of doing it is descriptive - Analytical, the type of analysis, quantitative. The collected documentation method includes reviewing the research and studies carried out on the topic and using the statistics and data required for Demographic Analysis collected from the statistics center the road and Urban Development Organization and the municipality of Tabriz.

The result was the lack of optimal distribution of facilities, welfare and wealth, the elimination of regional equality, the increase in the development gap and the loss of The main reason for this was also due to the Given that all the efforts of a balanced regional development are based on providing the best conditions and facilities for the comprehensive development of all areas, minimizing and ultimately eliminating the differences in quality of life between different areas and cities, it can be said that the importance of the present research is to attract the attention of development managers and planners to adopt policies and programs to reduce regional inequalities by understanding the different dimensions and angles of the existing situation and identifying the backward areas in the province. In this regard, it is necessary to target the development of deprived areas and cities to distribute economic, social justice in order to reduce inequality. In the meantime, Urban Development Planning and management in the form of regional and national programs plays an important role as a logical and useful strategy to raise imbalances in the region. 

The distribution of the distribution of cities by surface separation in cities also indicates that firstly, most of the provincial cities are located in the western half. Therefore, the spatial distribution of cities is not uniform in the province. Second, the province lacks a Level 2 city in the settlement system, and this is in turn considered a serious breakdown in the Space Organization of the urban settlements of the province. Thirdly, the distribution of Level 3 and 4 cities is higher in the western half of the province, and in this half, cities at levels 3 and 4 have developed with a smaller distance from each other