امكان سنجي توسعه فيزيكي بهينه شهر بناب

Feasibility Physical Development Optimal of Bonab City

امروزه يكي از موارد بسيار مهم و پيچيده براي برنامه ريزان شهري، تصميم گيري در مورد مكانه اي مناسب جهت گسترش آتي شهر و تعيين اراضي مناسب توسعه مي باشد كه اين مهم تنها با نگاهي جامع نسبت به تمام عوامل تاثيرگذار در جهت يابي توسعه ي فيزيكي شهر ، محقق خواهد شد. در اين راستا، پژوهش حاضر كه از نوع توسعه اي -كاربردي مي باشد، باهدف تعيين مكان مناسب جهت توسعه شهر بناب، با استفاده از روش توصيفي- تحليلي پرداخته است. بدين منظور هشت متغير مرتبط شناسايي شدند ابتدا براي تعيين اهميت شاخص هاي موردنظر جهت ارزيابي تناسب زمين، هر يك از معيار ها با استفاده از مدل تحليل سلسله مراتبي در نرم افزار Expert Choice ارزش گذاري گرديد. سپس لايه هاي مذكور توسط نرم افزارهاي GIS و IDRISI فازي شده و در طيف عددي صفرتا يك قرار گرفتند. در مرحله بعد تمامي لايه هاي فازي شده در هر يك از وزن هاي حاصل از مدل تحليل سلسله مراتبي ضرب و بدين صورت لايه هاي وزن دار فازي آماده شدند. درنهايت عملگر هاي ضرب، جمع، گاماي فازي 0/7، 0/8 و 0/9 روي لايه ها انجام گرفته و هم پوشاني لايه ها صورت گرفت. نتايج حاصله نشان داد گاماي 0/9 فازي بهترين همپوشاني را دارا است. با تقسيم بندي گاماي 0/9 مشخص گرديد كه 66.24 درصد از منطقه موردمطالعه (511.412 كيلومترمربع) در كلاس كاملا نامناسب و 9.56 درصد از منطقه موردمطالعه (73.8124 كيلومترمربع) در كلاس كاملا مناسب قرار مي گيرد. بر اساس نقشه نهايي طبقه بندي مي توان نتيجه گرفت پهنه هاي مساعد جهت توسعه شهر بناب بيشتر در بخش شمال شرقي و جنوب غربي قرار دارند.

Introduction Influenced by the global economy, urbanization has been accelerated in most parts of the world. This is actually changing the shape of the world. The growth in the urban population and the increase in rural migration to cities have fundamentally changed all the social, economic, environmental and physical aspects of cities. This turned them from a static and stable state into a dynamic environment replete with paradoxes. This population growth has had its own problems. One of the problems is the speeding physical development of cities. Urban physical development is a dynamic and continuous process and in this process, the limits and physical space at cities will increase both qualitatively and qualitatively in vertical and horizontal directions. If this process is unplanned, the environmental and physical aspects of cities will face with too many problems. This is why the optimal planning and site selection and development of physical aspects in cities is of much importance in their future development. Because establishment and creation of an urban settlement depend on the natural factors more than anything else since natural factors have a great importance in locating, distribution, physical and morphological development of the city and sometimes act as a positive factor and sometimes as a deterrent factor. According to population and physical aspects, the cities have undergone some major changes during the past few decades in a way that the unplanned and uncontrolled physical- spatial development of cities has resulted in the distraction of a large amount of agricultural fields and gardens around the city. This study attempts to investigate the physical development at this city in the recent decades and to determine the optimal physical-spatial development in the future using Geography Information System (GIS). Methodology this study is an applied research in purpose with Missing hyphen method. After collecting the document data and doing the required modification and completing the data through field study, an attempt was made to update the maps through observation and the information available in relevant centers and to digitize the maps and create some bases. To create layers and the required information for this study from the maps, the information available in the master plan development of Bonab and some other information were utilized. About eight factors were identified in order to study and evaluate land suitability for urban development including gradient, gradient direction, distance from the city, distance from the village, distance from communication ways, distance from waterways and land use. To determine the importance of target indicators to assess land suitability, first, the relative importance of each criterion was determined through analytical hierarchy model using software Expert Choice. Then, each of them was fuzzed using GIS and IDRIS and was placed in the numerical range of zero to one. In the next step, all fuzzed layers were multiplied in each weight resulted from analytical hierarchy model with integrating AHP model and Fuzzy model and thereby the weighted fuzzy layer was prepared. Results and Discussion According to the analysis, Bonab city located in a Plain area which is the average height of about 1600 meters above sea level. Bonab city has a population of 134892. Due to various environmental and human factors, Bonab city has been under constant changes during the past 30 years. These factors consist of village- city migration, job opportunities, a natural potential for physical development, and intercity and provincial roads. With the application of proper strategies of development and leading residential and activity centers to suitable lands, it is possible to stop development of residential areas in unsuitable lands and use resources in better ways alongside with preserving agricultural lands of the area. This means the authorities should prevent the wasting of these lands and orient the development of cities toward the lands where have low value concerning the environmental and natural factors. Conclusion The results of this study show that the physical- spatial development of Bonab in the recent decades has been fast and unplanned. The results indicate that the fuzzy gamma of 0.9 has the best overlapping and at last, the optimum gamma was divided into five classes of totally inappropriate, inappropriate, average, appropriate, and totally appropriate in the form of final maps of land suitability. an‎d it was identified that 66.24 % of the study region (511.412 km2) is located in the class of totally inappropriate and 9.56 % of that (73/8124 km2) is located in the class of totally appropriate. According to the final map of classification, it can be concluded that the optimum zones to develop the city of Bonab are mainly located in the northeast and southwest.