نوع مقاله : پژوهشی - کاربردی
نویسندگان
1 استادیار جغرافیا و برنامه‌ریزی شهری، دانشکده جغرافیا، دانشگاه تهران، تهران، ایران
2 استاد جغرافیا و برنامه‌ریزی شهری، دانشکده جغرافیا، دانشگاه تهران، تهران، ایران
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Introduction
Urban spatial structure can be considered as a partial or general description of the distribution of phenomena in urban geographical space. Cities can grow in different spatial structures and functions. This is the objective result of interactions between land and topography markets, infrastructure, laws and regulations, taxation, industrial development, distribution of socio-economic enterprises, transportation network, decisions of real estate planners and developers, and investors, businessmen and policymakers. Understanding the urban spatial structure is of paramount importance in formulating planning strategies and policy support to create habitable, vibrant, and densely populated cities that can be measured in terms of functions and activities. This type of spatial structure in one hand is a symbol of physical spaces and, on the other hand, shows the space of human activities in the form of social dynamism and urban vitality. The hypothesis of a monocentric model emphasized the concentration of employment in the commercial centers of the city, which was dedicated to commercial and residential land uses. Places were selected based only on distance from employment centers, but not all employment-related activities were concentrated in the CBD. Some production was located outside the CBD and in the areas with lower densities and less valuable land, which gradually led to the decentralization of employment from the CBD to the residential suburbs of the city. As transportation systems grow and develop in cities, the polycentric phenomenon is inevitable.
Over the past few decades, Tehran has grown from a traditional city with simple economic functions to a new urban phenomenon with the characteristics of a new industrial city. The uneven transformation of Iran's socio-economic system in the last century and the imposition of exogenous development patterns on Iranian society have disrupted its natural course. Meanwhile, Tehran, as the center and main hub of economic development and industrial development of the country, has provided the ground for its rapid and uneven development. The compulsory process of migration and activity around its periphery the last five decades has made the city expand on its new axis and develops new sub-center. Thus, the process of industrial development and urban development in Tehran has emerged in an unbalanced manner.
Methodology
In order to analyze the spatial structure of activities and employees, statistical data of the years 1996-2017 as well as data of the structural-strategic plan of Tehran were used. Kernel density was used for employee density and spatial autocorrelations such as general Moran I statistic, local indicators of spatial association (LISA) and Statistic for both employee and activity dimensions. The modifiable areal unit problem (MAUP) problem was also used to determine spatial units.
Results and discussion
Findings show that in the studied periods, the main density of employees has spread periphery the sub-centers. In the 1996 period, the main core of Tehran, which should be the high-density part of urban activity, did not have a large population. During this period, Tehran had a not so strong main economic center. The situation in which urban managers seek to reform the various comprehensive and structural-strategic plans in polycentric structure can play a prominent role in the management. In the statistical period of 2006, the formation of the nucleus of activity is in the 21st and 22nd districts of Tehran; That is, the district where the largest commercial-leisure and industrial centers of Tehran are located. On the other hand, the emerging cores expand into the sub-centers. In the period of 2011 and 2016, the eastern core of Tehran will be strengthened. Active areas in District 18 are emerging and taking shape. A strong center in Tehran's District 5, which was formed in the previous period, is also being strengthened. During this period, contrary to expectations, not only was it not added to the density of the central district, but its stagnation was stabilized. Then, the spatial pattern of employees and activities was analyzed. The results confirm the status of clustering for the employees of these statistical courses. Analysis of activities shows that the performance of Tehran is more service; as most of the unit includes this activity. On the other hand, the share of this activity along with the commercial district in the main core and sub-center and other space units of Tehran is high. Tehran takes on a special shape in terms of the distribution of activities. The southern districts are mostly engaged in activities such as assembly, transportation and industry. Health and Aid also has the largest number of employees in the southern parts of Tehran. Activities in the public sector and salaries, technicians and assistants, specialists, legislators and managers live in the northern areas of Tehran as affluent areas and from the axis of Enghelab Street to the north.
Conclusion
In Iran, oil revenues provide about 85 percent of foreign exchange earnings and play a major role in government budget, industrialization, and urban development. The rapid growth of Tehran and the concentration of the country's facilities and industries have caused other cities in the country to be considered as satellites of the capital of Iran. In fact, the reason for locating industries in Tehran is its consumer market. Tehran has become especially important with the formation of its new factory industries. Most establishments and factories were located in the south of the city, and as a result, the area gradually became an industrial area. Therefore, in the development process of Tehran, the new plan of the city was greatly affected by the economic and physical performance of industries. On the other hand, due to the congestion and inefficiency of scale economies, it entered the broadcast stage. In subsequent urban development, new sub-centers accelerated their growth, and peripheral areas were integrated into urban contexts. Industrial decentralization policies from Tehran slowed down the establishment of industries in Tehran over a period of time, causing the process of industrial decentralization to be transferred to the areas around Tehran in a chain and in connection with Tehran. Therefore, the results of this study can be a guide for urban planners and managers to be able to evaluate the objectives of the structural-strategic plan of Tehran and to propose the main and main sub-centers for researching its polycentric structure.
کلیدواژه‌ها [English]
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