آشكارسازي تغييرات كاربري اراضي شهراردبيل با استفاده از تكنولوژي RS و GIS

Change detection of land use in Ardabil city by means of GIS and RS Technology

از آنجايي كه اراضي كشاورزي منطقه دشتي اردبيل ازارزش بسيار زيادي به لحاظ تامين مواد غذايي دارد و بايد سياست­ هاي استفاده مناسب از كاربري ­ها در اين عرصه به خوبي مديريت گردد. لزوم تعيين روند و نرخ تبديل پوشش اراضي براي برنامه­ريزان توسعه به منظور برقراري نظام­نامه استفاده از زمين ضروري است. به اين منظور اطلاعات پوياي زماني سنجش از راه دور مي­تواند نقش مهم و موثر براي پايش و تجزيه و تحليل تغييرات كاربري با استفاده از تكنيك­هاي آشكارسازي رقومي تغييرات كه فرايند تعيين يا توصيف تغييرات درنوع پوشش اراضي و وضعيت استفاده زمين براساس اطلاعات تصاوير چند دوره زماني است، داشته باشد. فرض اساسي در استفاده از داده ­هاي دوركاوي در اين مطالعات بر اين پايه است كه مي­ توان روند صعودي و نزولي تغييرات بين دو يا چند تاريخ را شناسايي و در سال­هاي مختلف مورد تعقيب و پايش قرار داده و روابط متقابل ميان پارامترهاي طبيعي و اجتماعي و اقتصادي را كشف نمود. در اين بخش از روش و متدلوژي سنجش از دور بر مبناي تصاوير ماهواره ­اي موجود و در دسترس با توجه به تكنيك ­هاي طبقه ­بندي نظارت شده بيش­ترين شباهت براي شناخت تغيير كاربري اراضي در محدوده توسعه يافته شهر اردبيل استفاده شد.

Since agricultural plain lands of Ardabil have been important in providing food stuffs, and due to the necessities of land usage management in this section, determination of process and change-rating of land cover I important for developers. In this regard, dynamic temporal data of remote sensing can play an important role in searching and analyzing of land usage change which is done by means of numerical change detection techniques in which the descriptive process of changes in covering variety and situation of land use is based on the temporal series image data. Basic hypothesis in using remote sensing data is on the base of these criteria that claims the ascending or descending nature of changes between two or more periods is recognizable, and by comparing the related data from different years, we can detect mutual relationships between natural, social and economic parameters. In this study, maximum likelihood supervised classification and change detection techniques were applied to Land sat images acquired in 1990 and 2007, respectively, to map land cover changes in the Ardebil city. A supervised classification was carried out on reflective bands for the four images individually with the aid of ground truth data. Ground truth information collected were used to assess the accuracy of the classification results. Using ancillary data, and expert knowledge of the area through GIS further refined the classification results. Change detection technique was used to produce change image through cross-tabulation Changes among different land cover classes were assessed. During the study period, a very severe land cover change has taken place as a result of agricultural and urban development projects. These changes in land cover led to vegetation degradation and cropland in part of the study area.