آشكارسازي تغييرات كاربري / پوشش اراضي شهر گنبد كاووس با استفاده از سنجش از دور

Detection of land use / land cover changes in Gonbad-e-Kavus City using remote sensing

توجه به توسعه فيزيكي شهري پايدار، به عنوان يك ضرورت اساسي در برنامه هاي توسعه ي شهري، حاكي از اهميت اين موضوع در تقويت جبهه هاي فرهنگي، اجتماعي و كالبدي شهر مي باشد. تغييرات پوشش سرزمين و توسعه شهرها سبب تخريب زيستگاه هاي طبيعي و كاهش تنوع زيستي شده است، يكي از روش هاي مورد استفاده برنامه ريزان جهت كنترل روند تغييرات پوشش سرزمين و كاربري اراضي، مدل سازي مي باشد. اين مطالعه با هدف مدل سازي تغييرات كاربري اراضي شهر گنبدكاووس با استفاده از LCM انجام شد. آشكارسازي تغييرات كاربري اراضي با استفاده از تصاوير ماهواره لندست متعلق به سال هاي 1366، 1379، 1389 و 1393 انجام شد. مدل سازي نيروي انتقال با استفاده از پرسپترون چندلايه شبكه عصبي مصنوعي و 10 متغير انجام پذيرفت. سپس با استفاده از مدل پيش بيني سخت و دوره واسنجي 1366 تا 1379 مدل سازي براي سال 1389 صورت گرفت و براي ارزيابي با نقشه واقعيت زميني سال 1389 مورد مقايسه قرار گرفت، در پايان نيز با استفاده از دوره واسنجي 1379 تا 1389 پوشش سرزمين سال 1404 ،1419 و 1429پيش بيني شد. نتايج نشان مي دهد در كل دوره مورد مطالعه به ترتيب ۲۸۵۸/۳۲ كاربري شهري و ۱۱۰۶/۴۷ اراضي آبي افزايش داشته و همچنين به ترتيب ۲۳۳۱/۷۷ اراضي باير و ۲۱۳۵/۵ هكتار از وسعت اراضي ديم كاسته شده است. نتايج مدل سازي نيروي انتقال در اكثر زيرمدل ها صحت بالايي را نشان مي دهد. نتايج مدل سازي با استفاده از زنجيره هاي ماركوف نشان داد كه در سال هاي آتي شهر گنبدكاووس توسعه شديدي خواهد داشت و اغلب به سمت شرق و جنوب خواهد بود، همچنين توسعه در سمت شمال و غرب نيز وجود دارد كه در صورت عدم توجه باعث توسعه حاشيه نشيني خواهد شد.

Introduction: Cities are always influenced by various forces and factors. With social changes، demographic displacement، economic change، and technological innovation، they are transformed. As the population grows، activity and investment are greatly expanded، and the physical system of the cities undergoes fundamental changes.Along with the rapid urbanization process، a large amount of natural lands، such as forests and wetlands، has turned into agricultural land and residential areas. Quick land use changes have had profound effects on natural and human environments. For example، agricultural development and structures lead to deforestation، soil erosion، water basin degradation، and biodiversity loss and pollution. In addition، changes in the use of agricultural land and the acceleration of urbanization have led to an increase in impenetrable levels، which has led to the development of a transport network and the accumulation of non-disturbing contaminations associated with surface runoff. Due to these great effects، the detection and anticipation of land use change has become an important topic in environmental management and land use planning. At their initial stagesof formation، most of the cities in Iran were established near or among thehigh-quality agricultural lands with the purpose of using high-quality soil foragriculture and then these lands were gradually buried under the cities throughvillages development and changing into cities and then development of thecities. Accordingly agricultural activities were inevitably receded to the poorlands. Materials & Methods: To access fundamental maps for analysis of data and use of different methods to achieve the goal of this study، satellite images related to years 1987،2000 and 2010 are used. Topographic maps of 1:50000 scales obtained from the army geographical organization are used for geometric correction. At this stage geometric correction was performed on the images using image sensor TM of the year 2010 image - vector، were georeferenced. To perform this task، 42ground control points with appropriate distribution in road junctions، water channels and etc were used.To process data، make models and analyze output…،In this research، land cover maps produced in the years 1987 and 2014 as inputs of the LCM model were selected to analyze the changes in the region and predict land use changes in the year 1404. The LCM model requires two maps covering land belonging to different times as inputs . In this study، Gain and losses، net change، unchanged regions، Transition، from each user to another in different classes of land cover، was mapped and mapped to the model analysis section of the model.ENVI، IDRISI Selva and ARCGIS10 are used and to categorize uses most-probability-models and methods are used and finally Ca_Markov model was used to predict and calculate changes in 2025،2035 and 2045. Results & Discussion: Multitemporal images used in this study were used in mapping land coverafter geometric correction. With regard to existing images and maps and the condition of the area under investigation and field visit for mapping land cover، five types of applications are discovered for land namely، residential land،irrigated land، rain-fed land، sterile lands، parks and gardens. Altogether during this time،27ys، agricultural land and residential land cover has increased and sterile land and rain-fed land cover has decreased. Agricultural lands consume a huge amount of water due to exploiting water from deep holes and land overuse that has turned rain-fed lands and sterile lands into water-fed and residential lands. As the table of predicting areas indicates the greatest increase about 1744/74 hectares belongs to agricultural lands and 1741/79 hectares belong to urban lands which includes: residential lands، trade centers، military areas، hospitals، higher education institutes and etc. The least change، 274/18 hectares belong to parks and gardens in and around the cities. The most decline 2261/59 hectares، is observed in sterile lands. Of the total net changes، one can conclude that urban use has increased and all land cover has become largely urbanized، as well as water lands with the rise and development of deep wells ... The need to preserve these lands from the physical development of the city in this direction is essential in order to develop the sustainable development of the city. There are many undeveloped lands in the old days، due to the lack of water and the lack of facilities that، with the advancement of agriculture، turned these lands into agricultural lands، as well as landless areas today are mostly in the suburbs or around the city، mainly because Farmers، in hopes of landing and declaring a few years away، leave the land in a state of desert، in order to become urban development، and to see huge profits، which is one of the most important issues in our country، and many offenses in This is the case where the city of Gonbad-Kavas is not an exception to this rule. Parks and Gardens also have a rational increase in the city، and in urban development projects، parks have been created and the size of the garden is very low in the city of Gonbad-Kavoos. By predicting changes in usages، it is concluded that the most change will take place in urban usages and rain-fed and sterile lands with dramatic increase and decrease respectively and with Gonbad e Kavoos population growing، some steps should be taken to develop the spatial area of the city so as to prevent destruction of fertile lands for the sake of human construction. Conclusion: In this study the effect of physical expansion of Gonbad e Kavoos city on agricultural lands is investigated. Findings indicate that during 45 years around 1880 hectares of fertile farmlands surrounding the city are destroyed. The main reason behind this destruction is the horizontal expansion of the city. Hence، as one of the fundamental bases of sustainable urban development is the increase of city density، it is concluded that horizontal expansion of the city is totally in contradiction to sustainable development and it leads to more instability of the city