آشکارسازی تغییرات فضای سبز تهران با استفاده از داده‌های سنجش از دور

فضای سبز یکی از کاربری های حیاتی شهر برای تداوم زندگی در شهرها به حساب می آید و بدون آن فعالیت سایر موجودات زنده از جمله انسان کاملا و یا حتی غیر ممکن می گردد. بنابراین کمبود و کاستی در امر مدیریت این کاربری می تواند تاثیرات مخربی بر روح و روان شهروندان بگذارد. در دهه های اخیر، با توجه به رشد مهاجرت به سمت استان تهران و تقاضای هرچه بیشتر به مسکن و مناطق صنعتی در این استان کمبود فضای سبز بیش از پیش در این استان نمایان شده و باعث بروز مسائل عدیده ای همچون مسائل زیست محیطی، تشدید آلودگی هوا و افزایش ساخت و سازهای بی رویه شده است. از این رو هدف از مقاله حاضر ارزیابی فضای سبز شهر تهران و مقایسه روند تغییرات فضای سبز با استفاده از تصاویر راداری سنتینل-1 و لندست-8 در سال های 1393و 1399 می باشد. به منظور آشکارسازی تغییرات، پس از پیش پردازش ماهواره ای برای پایش تغییرات به طبقه بندی با استفاده از روش جنگل تصادفی پرداخته شده. بر این اساس دقت کلی طبقه بندی 47درصد و شاخص کاپا 0.39 استخراج گردید که با توجه به نوع داده های مورد استفاده دقت کلی نشان دهنده تطابق خوب واقعیت و تصاویر ماهواره ای داشته و با استفاده از ویژگی های بافت ماهواره ای راداری، نشان داده شد که طی سال های 1393و 1399تغییری در وسعت  فضای سبز وجود نداشته و در برخی از  مناطق شهر تهران سرانه ی فضای سبز  رو به کاهش می باشد.

detection of changes in tehran green space using remote sensing data

in recent decades, due to the various facilities in big cities that have caused the expansion of cities and urbanization and the increasing desire of citizens to live with a machine, this change in life pattern has also caused an increase in environmental pollution, difficult conditions for the livability of human life space, such as (the destruction of urban and suburban vegetation and the loss of ecological balance. the expansion of the population of cities and excessive population density in cities has caused the destruction of the natural environment and the construction of artificial structures that require physical and it has made the human spirit more visible to the environment. considering that iran is one of the countries located in the dry belt of the world, the cities to deal with noise and air pollution, as well as reduce environmental stress more than any other point to the space they need green. considering the many problems that we see in changing the urban structure today, the heterogeneous quantification of the environment has been considered as a goal in landscape ecology, so that recently there have been efforts to develop methods in order to quantify the spatial heterogeneity (complexity and variability of the system characteristics, including the mosaic spatial layout of the land surface) (time and space) the features of the land have been done. terrain metrics are a useful tool for expressing the mosaic pattern of urban green spaces and its changes in connection with urban development processes, which, in addition to interpreting the effect of the aforementioned processes on the ecological characteristics of the environment, can be used in decision making related to the growth of the city, distribution of uses and urban green space development planning. therefore, according to the existing problems in defining and determining the urban green space, the application of remote sensing science, which is considered a powerful tool in the management of urban resources, and by providing the facilities of this science in order to provide up-to-date information, digital processing of images and the possibility of comparison sometimes the data has helped experts to monitor the changes of the green space over time. also, by using remote sensing in combination with terrain measurements, it can improve the understanding of urban spatial structure and change processes. today, the high speed and extent of changes, both structural and process, in the face of the land, which are caused by destructive human activities, have made planners face many issues and problems. the present study was conducted in order to evaluate map production using sentinel-1 and landsat-8 radar images using local climate method and vector machine in tehran metropolis. using the proposed method, it was determined that the central and southern parts of tehran have a very concentrated residential structure, so that urban green spaces are rarely seen in the urban context, while the green spaces in the north of tehran are scattered among the contexts. it is residential, which indicates the existence of private green spaces in this part of the city. also, in the south of the city, due to the presence of fine-grained texture in this area, due to the presence of residential centers in these areas, compared to the residential texture of the northern parts of the city, in the central and southern areas, private green spaces do not exist or rarely exist, and this warning increases. heat islands and higher temperature are in the south of the city. maps produced using remote sensing can be an alarm for municipal managers who can prevent future problems with planning and management. also, considering the important role of green space in the morale of citizens and crime reduction, it is necessary for city managers to pay enough attention to the issue of reducing green space and the lack of proper distribution of use in tehran, because neglecting this issue can lead to other problems. it created compensable for the citizens.