عنوان مقاله [English]
Metropolises are emerging phenomena that affect a wide range of surrounding space. This effect over time leads to the expansion of the metropolitan area. The current research has been compiled with a general descriptive-analytical approach and using available documentary data and statistical data. Excel and Spss statistical software and ArcGis spatial processing and description software were used in database preparation and data analysis, and ANN nearest neighbor index was used to determine the activity distribution pattern, and Moran's Spatial Autocorrelation Model was used to check the distribution rate. Is. Based on the results of the research and investigations of the Qazvin metropolitan area in terms of activity, it can be said that the Qazvin metropolitan area has a dominant linear structure with a trend and development towards the formation of a radial-annular structure in its southern half. Also, the spatial structure of the metropolitan area of Qazvin has been made in connection with the expansion of relations and economic connections with cities and rural areas, especially in the southern part of the area.
Metropolises are emerging phenomena that affect a wide range of surrounding space. This effect over time leads to the expansion of the metropolitan area. This phenomenon first started as a result of the concentration of capital, activity and population in the most important cities, and then it was accompanied by the decentralization of population and activity in a wide area (Gholami, Zamani, 2019, 13). It is the level of the countries that allocate a large amount of human and material forces of the countries to organize the category of development in cities and have a very high importance in urban and regional systems (WU, 2008). The population of cities, especially in developing countries Development is increasing, it is predicted that more than 3 billion people will be added to the population of urban areas during the period of 1999 to 2030. Of this amount, 90 percent will be progressing in urban areas (Saif al-Dini, 2010: 157). Urban area is an interconnected set of urban components and elements, including residential units, commercial, cultural, recreational and administrative complexes, road network and public service spaces. These unique areas in most cities of Iran, due to the way they were formed and transformed during the historical periods, also after the arrival of modernity, along with their unique structure, have a different physical-spatial structure compared to other settlements, a structure that Due to the accumulation and interaction of various urban functions, market forces, citizens' preferences, and known and unknown spatial relationships, it becomes more complicated.
This research is descriptive-analytical and practical in nature and purpose. The method of collecting statistics and information is in the form of documents and books, and it is extracted by referring to the organizations and departments of the province and the available statistics. Spatial description and processing software, including GIS, have been used to analyze the data of the spatial structure of the studied area. One of the most important analysis models used is the nearest neighbor index (ANN).
The population structure of the studied area has changed along with the structure of the whole country. The base of the population pyramid is increasing from 1355 to 1365. Approximately, it started to shrink from this year onwards and reached its lowest level by 2010. In the second half of the decade of 1375-85, due to the population born two decades before entering the reproductive age, an increase in the base of this pyramid is observed, this increase continued until 1390. On the other hand, with the increase in the age of the existing population, the increase of the middle-aged and old population can be clearly observed. These developments have occurred both for the whole country and for the studied area of Qazvin province. This difference indicates that the Qazvin metropolitan area has accepted more of the young job-seeking population in the past few decades. In relation to natural ecosystems, the sequence of ecosystems in the studied area indicates that the regression process is prevailing. Severe soil erosion due to unwise use, contamination of surface and underground water sources with industrial, agricultural and urban pollutants, reduction of plant and animal genetic resources due to the loss of habitats and loss of their unity, caused by large-scale infrastructure activities For example, the construction of freeways and highways will make the future natural landscape of the region unstable and dark to some extent. The main visible trend is industrial development regardless of ecological standards and the issue of sustainable development. Due to the fact that this area is in dire need of development due to various natural, economic-social, cultural and even political reasons, we should not lose sight of the principle that development in a suitable context and by observing the natural standards and nature of nature will be able to achieve its goals. Answer the question in the long term. In this research, the spatial structure of the studied area was analyzed in four parts: land use, activity structure, communication network, and population structure. The result of the research is as follows; The spatial structure of the Qazvin metropolitan area in different parts is a concentrated structure in the south, southwest and east parts, where the most settlements and service and industrial uses have also expanded in these areas. In the field of land use analysis, the land use in the study area is based on the settlement, formation and establishment of almost the majority of urban and rural settlements in the southern part of the study area, according to the fertile plain of Qazvin, as well as the presence of the settlements in the southern part. It includes good quality water sources and good soil and expansion of agricultural activities in this area. In relation to the communication network of the region, the structure and nature of the development of Qazvin city has had a decisive impact on the interaction-communication pattern. So that under the influence of the sovereignty and superiority of the city of Qazvin on the functional structure and the subsequent dominance of spatial converging forces, communication networks have been formed in the form of dominant linear routes (with radial sub-branches) in response to concentric spatial relations. Different urban patterns include linear, single-center, multi-center, scattered, and radial patterns, which different cities of the world have taken a shape according to these patterns. But in relation to the expansion of the studied area, this area has a composite structure of these patterns, so that it can be said, "the physical pattern of the spatial organization of the studied area has a dominant linear structure with a trend and development towards the formation of a radial-annular structure in It is the southern half of it." In the process of the formation and development of the Qazvin metropolitan area, at first all tendencies were centrist and after some time with the completion of the capacities of the central region in a stage of its development which is accompanied by rising land prices, centripetal forces and divergent trends overcame the centripetal forces and convergent trends. and the studied range enters the projection stage. This projection is such that the new residents, especially the low-income groups, will not have the ability to settle in places where land prices are high. Based on this, a part of the population and activity in the refining process remains in the center as a choice, and another part is projected out in the drifting process. Based on this relocation process, the spaces of the metropolitan area of Qazvin are divided, so that the central area will be allocated to services, the surrounding areas to industry, and finally, the peripheral areas will be allocated to agriculture. In the aforementioned process of location selection, the most important effective factors in the location selection of population and economic activities are: land price, transportation cost, existing laws and regulations, and plans and programs in progress. The studied area also followed this process, so that the forces Centrifugal and divergent trends, service-oriented, dominance of distribution relations, expansion of market territory are observed in inter-regional relations.