Iran before the present century has owned a relatively modest system, but in the last six decades, the capitalization development within the oil-based economic framework has led to urban system spatial imbalances in the country. On the other hand, the Spatial Equilibrium of the Urban System in National- Regional Levels is in the pledge of Spatial Equilibrium in region. So, the present study, with the objective of examining the Spatial Equilibrium of the Urban System in National- Regional Levels for 1956- 2012, has been performed. This method is descriptive - analytical. The statistical society includes the urban settlements in the past 60 years and data collection method is as evidence. In this study, in order to examine the spatial equilibrium of urban system in Iranian Provinces, the Entropy Model was used. This is evident that considering that the urban system tends to a desirable spatial equilibrium, but because of the difference with normal rate, the imbalance of spatial equilibrium of the urban system in national- regional levels in Iran is remained as in the case of the number of urban settlements, it is more evident.

The problem of spatial equilibrium and disequilibrium has always been one of the main concerns of policy makers and regional planners in Iran. Two prerequisites, which have not been considered by regional analysts in Iran, are highlighted to explain this problem: First, the recognition of theoretical foundations of place-based and place-neutral theories, and, second, the use of integrated and coherent statistics such as the MRIOT. The main purpose of this paper is to examine these two issues while using a multi-regional model with special emphasize on the feedback effects, based on following three questions: Is there a direct relationship between the size of GDP of different regions with their spillover and feedback effects? Which regions have a greater role in the spatial equilibrium? And finally, which sectors do play a greater role in the spatial equilibrium of the country? For answering the above questions, for the first time in Iran, the MRIOT is calculated. The MRIOT comprises nine regions based on the latest approval of the Supreme Council for Spatial Planning using the FLQ-RAS mixed method, within the framework of seven economic sectors for year 2011. Findings show that: First, there is no direct relationship between the size of GDP and the spillover effects of the regions. Second, the feedback effects of the regions with smaller GDP are higher which would potentially play a greater role in creating spatial equilibrium in the country. Third, the feedback effects of the agricultural related industries in eight regions are higher than that of the other economic sectors. This suggests that, this sector can be considered as the driving force behind the spatial equilibrium in the country.

IntroductionVariety & diversity of viewpoints about urban structural–functional growth & development shows the complexity & expansion of the "city" category and the related issues which, in turn, indicates dynamic characteristics of the city. After a century of introducing organized and systematic theories in this filed, what worth surveying is the effective skeletal-social-economical outcome of these views on the development & structure of the cities. The theories on development & structure of the cities have one characteristic in common, i.e., one-dimensionality which normally accompanies with a skeletal view. Also, one of the main goals of these theories is to reach spatial balance as the result of convenient urban spatial structure. MethodologyThe writer has used eclectic method of analytic–documental and using gravity theory has estimated the extent of spatial interaction among urban regions. Then, the extent of regions integrity has been obtained using space syntax technique. And at last, causal relation between these factors is equated using linear regression.Results and Discussion The paper aims to study spatial structure of Bojnourd and the role of functional-skeletal elements in shaping this structure. The study is performed through spatial interaction of land uses and the extent of urban network integrity to access appropriate spatial structure. One of the issues raised in the paper is how to create balance through production and attraction of interurban journeys via space syntax model and technique. This article assumes that correlation between spatial interrelation and local position of urban regions is one of the skeletal effective elements that are helpful to spatial balance realization. The writer tests the hypothesis on Bojnourd city to determine the position of two major factors, i.e., spatial interaction and place situation of each of 31 urban regions for study of spatial balance of Bojnourd. To accept the issue that spatial balance of a particular city such as Bojnourd depends on the proper spatial interaction, integration in urban areas and the appropriate spatial relationship within the evolutionary process of an active system between these two factors, it has been tried to study spatial interaction of the areas and their rate of integration in the city and also analyze the amount of correlations between these two factors and at last review the impact of these factors on the spatial balance of the city. ConclusionSo, spatial-anatomical structure of the city is unbalanced and there is little integrity between the regions. In the case study, the study of spatial interaction of regions and their integrity and interrelation indicates that spatial balance is an important and fundamental indicator which has been found less evident about the city of Bojnourd. The result of research shows that either correlation between place situation of the regions and spatial interaction does not exist or is at least.Spatial interaction of the areas in the case study and their integration and the relationship between these two factors indicates that the typical spatial balance is considered to be essential and important which is less noticeable as the result of this research reflects in the city. Therefore, the spatial interaction of the areas, their integration and their interrelationship are among the factors affecting the spatial balance which can be used to create spatial balance. Regarding this issue, there is a causal relationship between the two variables which can be formulated to layout spaces. This method is exerted on the case study (Bojnourd) which can afford to calculate the ideal syntax of urban components according to the formula derived. Consequently, ideal interaction of a region can be measured based on the structure of that region, while in reality the obtained amount is much different from this value. We call this value the "error". Thus, presence of such an error rate according to Table Two shows that the spatial structure of Bojnourd is defective and out of balance. As a result, the syntax must be changed in such a way that the error rate reaches its minimum. So, by studying the existing differences among the models and the reality of spatial interaction of the areas of Bojnourd, one can slowly lead urban system toward more spatial balance in its natural bed through physical, social, economic and cultural measures

Based on the notions and assumptions of the discourse of “new urban regionalism”, there is a close relationship between the "spatial morphological structure" and the "spatial division of labor" in a megalopolis region, and solving existing problems in one without another is not possible, because they can either act in the direction of positive reinforcement and support, or in order to weaken and become an obstacle to each other; therefore, what is meant by the problem of achieving equilibrium and integration in the spatial structure and the functional system in a megalopolis region, will not be possible without recognizing the nature and relationship between these two. The reviews done the research shows that "spatial morphological structure" and "spatial division of labor" in Tehran's megalopolis region during the recent decades has not been able to support each other and significantly reduce the spatial non-equilibrium in the region. Therefore, according to the results obtained in the framework of this study, the "spatial morphological structure" and "spatial division of labor" in Tehran's megalopolis region during the recent decades (1345-1390), has been accompanied by a significant reduction in the spatial non-equilibrium in the region, though, the trend of transformations is on the move. One of the strategic implications of this is that the future issue of the Tehran's megalopolis region is to be more focused on the peripheral population poles and the improvement of the level of performance of the city itself in order to accept transnational functions and create alternatives and opportunities for roles and the tasks that will be assigned to them in the future. Just as in the prior years the industry sector has gradually shifted to the service sector, in the future it also seems necessary to give up the services sector to itself periphery and oppose the acceptance of the fourth sector of the global economy (such as; Information, communication and cultural economy).

Regional income inequality has been the subject of academic debates since 1950s. However, theoretical bases on regional disparities provide conflicting views on relations between inequality and national growth. Some researchers believe that in the first stage of national economic growth, regional inequality is a natural phenomenon that stems from lack of coordination between the spatial system (regional economic growth) and the national system (national economic growth). Over a period of time, however, with increasing movements of production factors (labor and capital) among regions, regional inequality will be minimized or possibly eliminated. While, some other researchers like Myrdal and Hirschman claim that spatial movement of production factors increases regional inequality. They believe that only government intervention can reduce gaps among regions in the process of development. Amos Terrassi and Lessman believe that regional inequality follows a pattern of increase-decrease-increase. The cause may be a fundamental and systematic change in economic activities, such as increasing in suburbanization or moving to a service-based economy. Also there is a group of thinkers who claim that scale economies increase regional disparities. Thus, there is a positive correlation between regional inequality and economic growth. Therefore, literature review on regional disparities shows that theories and empirical studies have an unclear message about the evolution of regional disparities over time. The purpose of this paper is presenting a typology of theoretical and empirical studies on regional disparities. According to investigations, theoretical and experimental approaches toward regional disparities refer to two economic theories: “neoclassical economic growth” and “new economic geography”. Neoclassical economic growth theory believes that regional disparities will decrease over time, while Krugman belonging to new economic geography theory claims that regional inequality will increase. We have classified regional inequality approaches into three categories based on two economic theories: 1) spatial equilibrium 2) spatial disequilibrium and 3) in-between approaches. Spatial equilibrium theorists refer to neoclassical theory. These theorists show that regional disparities will reduce over time and there is a negative correlation between national income growth and regional disparities. Spatial disequilibrium theorists refer to new economic geography theory. These theorists are divided into three groups. The first group who presented their studies before Krugman's theory believe that capital and labor move from less desirable area into growing areas. The second group believes that regional inequality will increase after completing Inverted-U model (which proposed by Williamson). The third group claims that there is a positive correlation between economic growth and regional inequality because of scale economies. Recent studies in the field of regional disparities provide a view that has been proposed as an “in-between approach”. This approach believes that relation between regional disparities and economic growth depends on development level or scale of regions. In some areas the relation between growth and inequality is positive, while it is negative in other areas. This typology shows that we are not sure about pattern of regional disparities evolution. However, it seems that these days, in-between approach is more reliable.

In recent decades, the concept of spatial justice has gained special importance in marginal settlements. Injustice in the distribution of urban services has caused irreparable damage to marginal settlements. The absence of radiation in services in such settlements resulted in the formation of spatial imbalance and increased class gap. Considering the concepts of spatial justice to meet social, economic, physical and optimal distribution of services and facilities, attention to basic needs of citizens in marginal settlements is critical. in this regard, the present study aimed to explain the physical and functional components affecting spatial justice in urban poverty cores of Mashhad metropolis. This research is applied in terms of practical method and in terms of descriptive - analytical purpose. data collection method - library and field methods have been used to analyze the data as well as content analysis methods, relative Shannon entropy method and multivariate regression. The results obtained by the relative Shannon entropy show that the distribution of service functions in the two nuclei of Golshahr and the Ghaleh Sakhteman are deprived of spatial equilibrium and is deprived of spatial justice, and the core of the Khaheh Rabi and Alteymour into two enjoy and semi- enjoy categories. On the other hand, the results of multivariate regression show that the physical diversity is the most important factor in realization of spatial justice in the marginal settlements.

Spatial imbalance in Tehran's metropolis and the metropolitan area has intensified despite the long history of decentralization policies. Many factors have contributed to this problem, but it is necessary to identify the driving forces to know the future directions. The research seeks to identify the levels and clusters of factors of this spatial imbalance and present future scenarios based on driving forces. Experts' opinions were obtained about the factor relationships that were known in the subject literature. These factors were categorized by MICMAC software and Interpretive Structural Modelling. Also by Scenario wizard software and Cross-impact balance analysis, driving forces were analyzed and logical scenarios were presented. Based on the findings, the government establishment factor is the most fundamental level. The population settlement pattern factor is the uppermost level. The population settlement pattern and physical growth are the most important variables in the dependent cluster. Industrial concentration, urban management, capital concentration, and population concentration are the most important variables in the Linkage cluster. Government establishment, decision-making centralization, service centralization, infrastructure centralization, economy centralization, extra-urban activities, and urban plans are the most important variables in the effective cluster. Among the ten logical scenarios, the top four scenarios were considered. Even if the best scenario occurs, it is still very far from ideal conditions. But if unfavorable scenarios occur, the conditions will be very close to the maximum possible crisis. The spatial imbalance in Tehran's metropolis and the metropolitan area is going to become more critical in the future.

Irregularity of spatial organization in developing countries (third world) has been arisen from socioeconomic and political structures. The resonance of aforementioned mechanism have been created issues such as regional imbalances. Rupture of the spatial organization and lack of non-hierarchy based relationship between the settlements are one of the main problem in the spatial and regional development of Kurdistan province. On this basis, the present study aims to analysis the spatial organization of Kurdistan province and its changes during the seven census period (1335-1390). In this context, the determination and establishment of a hierarchy of human settlement is an essential and effective base for population distribution, activities, services and functions at different level of spatial development. The main purpose of this research is an investigation upon urban systems, spatial organization and distribution of human population in the study area. The research method is based on the nature of the subject which is combined of analytical and descriptive method. Along to the analytical approach of methodology that has been used in this research in order to gain to spatial equilibrium variety of models and index including: growth, size and spatial structure of city, the rank-size rule, urban primary index, entropy coefficient, Gini coefficient, Lorenz curve SWOT analysis and etc. were used. The result indicates that there is a remarkable spatial imbalance in spatial organization and urban systems in Kurdistan province. Together these results provide important insights into the fact that to reach for balanced and sustainable development in the spatial organization context, creating same opportunities, equal distribution of facilities and services are inevitable.

During the recent decades, regional equilibriums and balanced distribution of the population have been one of the great concerns for the planners and regional development thinkers. In this way, cities as the main place of habitation and the most effective place in population movement, has got a significant position. Therefore, the main question of the paper is as follows: what is the optimized amount of the population in the cities? And how the population of a region can be equilibrated? Predicting the population in cities of the district of Azerbaijan within the 2022 Prospective and its planning based on rank – amount modification model appropriate with the elasticity and anthropy of the urban network, the author suggests the optimized amount of the population of the Azerbaijan cities and consequently to create an equilibrated spatial, he introduces the required policies to increase or reduce the rate of population growth in Azerbaijan.

The present study is aimed at explaining the spatial organization of the Khuzestan province system Settlement with emphasis on the role of oil. Oil has been the primary mechanism of formation of the Khuzestan Space organization for the last hundred years and has influenced other mechanisms. It is seen primarily as urbanization and polarization of population and activity. In the analytical field, firstly, using the spatial organization analysis models such as the class difference model and the nearest neighborhood model as well as the first urban indicators, the spatial organization of Khuzestan province is examined, and then to measure the impact of oil on the spatial organization. Housing System of Khuzestan Province Indicators their spatial distribution maps were prepared and analyzed in the form of three selected economic, social and physical variables. A system of information flows and communications and services and population movements under the influence of state bureaucracy have divided the province into the eastern and western or the oil and non-oil divisions. Spatial disequilibrium patterns in the Khuzestan province's oil-affected Settlement system in urban areas, severe imbalances in urban hierarchies, the weak role of middle cities, and thus the concentration of services commensurate with the distribution of deprived and marginalized populations of marginal and marginal cities. The spatial balance in the villages is the emptying of the villages in the eastern half of the province and the concentration of large villages in the western half.