تحليلي بر تغييرات كاربري اراضي در كلان شهرها با استفاده از آناليز تصاوير ماهواره اي در محيطENVI «مطالعه موردي: كلان شهر اهواز»

يكي از چالش هاي اساسي در فرآيند توسعه شهري كشورهاي در حال توسعه رشد شتابان آنها مي باشد كه اگر اين رشد حالت پراكنده و بدون برنامه ريزي به خود بگيرد مشكلات و مسائل متعددي را گريبانگير فرايند مديريتي و برنامه ريزي شهري خواهد نمود. شهر اهواز در كشور ما يكي از شهرهايي است كه در سال هاي اخير رشد شتابان و پراكنده اي را در عرصه ي توسعه ي اراضي شهري به خود ديده است. با توجه به نقشه ي وضعيت توسعه اراضي شهري مشخص مي شود كه اين روند سال به سال تشديد شده و منجر به چالش هايي در زمينه ي تامين خدمات و منابع زيرساختي در شهر گرديده است. در اين راستا با توجه به ضرورت مساله در مطالعه ي حاضر سعي شده است به روش «توصيفي-تحليلي» به ارزيابي تغييرات كاربري اراضي در كلانشهر اهواز مابين سال هاي 1989 تا 2013 پرداخته شود. گردآوري اطلاعات در بخش توصيفي از طريق مطالعه اسناد كتابخانه اي و در بخش تحليلي پژوهش از طريق استخراج تصاوير ماهواره اي (TM (Thematic Mapper براي سال هاي (1985) و (2013) از محدوده شهر اهواز انجام گرفته است. جهت انجام تحليل‏هاي آماري و بصري بر روي تصاوير ماهواره‏اي، از نرم‏افزارهاي Envi 4.8 و Arc GIS 10.2 استفاده شده است. نتايج به‏دست آمده، نشان مي‏دهد كه طي سال هاي 1989 تا 2013 نزديك به 23 درصد از سهم اراضي باير و زمين هاي كشاورزي كم شده و در طرف مقابل سهم اراضي ساخته شده از 35/16 به 55/34 افزايش يافته است كه بيشترين آنها مربوط به مناطق جنوبي و شرقي اهواز (قسمت هايي از مناطق 4و 5 و 6 شهرداري مي باشد).

Introduction One of the main challenges in the urban sprawl process of developing countries is their rapid growth that if this growth be a sporadic growth without planning would have numerous problems to urban planning and management.This unplanned growth, in addition to the destruction of agricultural land leads to urban tensions such as rising land prices, rising prices for urban services, and so on.In general, economic growth over the past decades in the country and the need to coordinate with global developments have caused most of Iran's major cities, such as Tehran, Isfahan, and Tabriz to be subject to rapid changes from the point of view of land use.Ahvaz is also one of these cities that has undergone fundamental changes due to its particular situation in the last few years. Material and methods The present research is applied study with descriptive-analytical methodology.Data collection in the descriptive section was carried out through the study of library documents and in the analytical part of the research, through the extraction of TM images (Thematic Mapper) from the years 1985 and 2013 for Ahvaz city.In order to achieve the goal of research and analysis of the images, the ENVI and GIS software were used.In this regard, after the preprocessing, the atmospheric correction and the selection of the most suitable bands for classifying and applying the maximum likelihood similarity (MLL) method, the controlled classification was performed in the ENVI software that the overall accuracy of the extracted map with the maximum probability algorithm in this research was calculated for 2013 (98.11%) and 1989 (94.23%).Then, land use changes in revealed in GIS software, and results were verified by checking severalexamples on the field. Result and discussion The findings of the research show that during the 24 years of study, the percentage of wasteland, gardens and green spaces has been reduced for the built land and roads.Reducing the ratio of gardens and agricultural lands in this area can be a major problem in land use changes in the present period.Also, by investigating the green spaces conditions inside the city, it was found that Ahvaz city, despite the improvement of greenery conditions in recent years, has been suffering from the shortage of this property inside the city due to the significant increase in population.The observed changes in the field of urban land development during the mentioned years showed that the areas with the most development in terms of land construction are among the most populous and at the same time the most migratory areas in Ahvaz which can be said that urban sprawl has grown, especially in the southern parts of the city. Result The results of this study indicate that the most land development in Ahvaz is located in the southern and eastern parts of the city.Although lands for future urban development is an opportunity for any city, but widespread and unplanned changes that mention the concept of scattered growth in the city of Ahvaz will make the providing of facilities, infrastructure and services difficult.