شناسايي پهنه هاي همگن جرياني بر اساس جابه جايي هاي فضايي و الگوهاي سفر- مطالعه موردي: منطقه كلانشهري تهران

Identification of the homogeneous flow Zones based on Spatial Motilities and Trip Patterns in Tehran Metropolitan region

الگوهای مختلف جابجایی فضایی، حاصل تأثیر عوامل مختلف سكونت، اشتغال و سطح درآمدند. در واقع نسبت به درجه انحراف از میزان رضایت افراد از ارائه این قبیل عناصر، پراكندگی و جابجایی­های فضایی اتفاق افتاده و الگوهای مختلف فضایی شكل می‌گیرد. بر این اساس، در سطح منطقه كلانشهری تهران با توجه به نحوه پراكندگی این عناصر، انواع مختلفی از جابجایی­های فضایی و الگوهای سفر شكل گرفته است. شناسایی پهنه­های همگن جریانی در این منطقه، علاوه بر آنكه دركی از ساختار فضایی منطقه به دست می‌دهد، می­تواند موجب برنامه‌ریزی برای الگوهای بهینه جابجایی­ فضایی در سطح منطقه شود. از این رو، در این پژوهش با بهره­گیری از روش توصیفی _ تحلیلی و با استفاده از ابزار تحلیل شبكه، بر اساس داده­های مرتبط با جریان سفر افراد در سال 1385 به عنوان در دسترس­ترین و مستندترین آمار موجود تا زمان انجام پژوهش، به شناسایی پهنه­های همگن جریانی و ویژگی­های آنها پرداخته شده است. در این راستا چگونگی برقراری پیوندهای ارتباطی میان شهرها در سطح منطقه كلانشهری و شكل­گیری سطوح مختلفی از كانون­های جذب و تولید سفر، راهنمای این پژوهش بوده است. نتایج یافته­های حاصل از این مطالعه، به شناسایی سه پهنه همگن در سطح منطقه كلانشهری تهران منجر شده است كه در هر یك از پهنه­ها جابجایی­های صورت گرفته بیشتر و منسجم­تر از سایر پهنه­ها بوده است. پهنه نخست به مركزیت كلانشهر تهران و كلانشهر كرج، بیشترین سطح از میزان روابط و جابجایی­ها را به خود اختصاص داده و همچنین پیوندهای قوی­تری را با سایر پهنه­ها برقرار كرده است، اما پهنه­های شرقی و غربی به دلیل فاصله زیاد از یكدیگر رابطه جریانی قوی را با همدیگر شكل نداده­اند.

The emergence of metropolitan areas is a phenomenon of the twentieth century and is a continuation of the prevailing trend of urbanization at the beginning of the eighteenth century. These new forms of urban areas are not only greater than previous ones in scale and more associated with decentralization, but qualitatively they are included in various types of systems. These new urban forms reflect fundamental structural dynamics that have changed the geography of urban areas. Different patterns of displacement can be the result of various factors including housing, employment and income levels, the factors that lead to different types of spatial mobility. In fact, depending on the degree of deviation from the consent of the provider of such elements, spatial mobility and displacement occurs in other areas. The impact of housing, employment and the ability to take advantage of the services required is very important and effective on formation of different spatial patterns. The Tehran metropolitan area including the city of Tehran and the surrounding population, economic and services centers has created a unique market for employment and residence. With regard to the distribution of housing, employment and services, various types of spatial mobility and travel patterns are emerging. The main objective of this research is identifying homogeneous areas in Tehran metropolitan area based on the number of flows and their convergence. By identifying and analyzing the characteristics of these zones, we can identify the flow conditions of spatial mobility and relations between the zones in the area and planning for it. The method used in this research is descriptive - analytical. In order to identify homogeneous zones, two elements, spatial mobility and physical links were considered. According to the available data, the most important of data is the origin-destination flow of people’s trips and to achieve the desired objectives, network flow analysis method was used. Thus, to identify homogeneous areas and to discuss spatial mobility trends in Tehran metropolitan area, network analysis features and fraction analysis - as a network analysis tool- was used. In addition, in this study, the characteristics of each zone were based on the calculation of the network including centralization and power, and how the presence or absences of certain central cities in each category are determined. Based on fraction analysis as a tool of network analysis, three main groups were identified in Tehran metropolitan area. The first category encompasses Tehran and Karaj metropolitan areas as well as the Central, South and Southeast cities in the region. The second category covers the north and northeast cities and the third category includes western most cities in the region. The zones comprise of cities in the region based on their distance from each other and their roles. The flow conditions are not similar across the area; the first zone, Tehran mega city and Karaj metropolitan, as central points have been allocated the maximum amount of connections and mobility and have also established stronger links with other zones. However, eastern and western zones have not been able to create considerable ties due to their great distance from each other. Tehran metropolitan area in addition to having a population of several million and a great deal of economic activities has a high level of functional linkages. Karaj metropolitan area has many economic activities in the form of manufacturing industries and factories based within it, and thus make the area an important place. The centers of Tehran and Karaj are attractive for travel from all over the metropolitan area while travel in other settlements occurs on a more local level. Most towns’ sphere of influence do not exceed the respective border city. Dependence on Tehran and then Karaj, shows the unbalanced system of movement and mobility in Tehran metropolitan area, while structural-physical changes in the current situation depends on new image of the area, mainly a mix of links and nodes and also emphasis on looking more and more integrated into the centers and areas in the form of a network of settlements. By identifying types of trips and their orientation, travel management can reduce the degree of concentration and amount of damaging trips. In addition, unnecessary trips can be eliminated through the development of communication technologies and network facilities and services and trips in the area can be planned in a balanced system.