نتایج جستجو برای: georas

تعداد نتایج: 87  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی ساری - دانشکده کشاورزی 1391

رشد اقتصادی جهانی در نیمه دوم قرن گذشته، نیاز به مواد خام برای تهیه زیر ساخت ها داشت. شن و ماسه، برخی از این مواد بودند. استخراج آن ها از سامانه رودخانه (بستر رودخانه، تراس های رودخانه ای، و ...) بسیار ساده تر از معادن سنگ است. علاوه بر این، به طور کلی مواد آبرفتی به دلیل فرایند ساییدگی که سبب جدا شدن ذرات ریز دانه از درشت دانه می شود، معمولاً دارای کیفیت بهتری از سایر منابع هستند (کاندولف، 1994...

2007
George T. Raber John R. Jensen Michael E. Hodgson Jason A. Tullis Bruce A. Davis

Lidar data have become a major source of digital terrain information for use in many applications including hydraulic modeling and flood plane mapping. Based on established relationships between sampling intensity and error, nominal post-spacing likely contributes significantly to the error budget. Post-spacing is also a major cost factor during lidar data collection. This research presents met...

Journal: :پژوهش های روستایی 0
عبدالرضا رکن الدین افتخاری مهدی پورطاهری طاهره صادقلو حمدالله سجاسی قیداری

rural community and their services, productive activities, because of strong relation with environment, from long bygone were exposed to disastrous natural power. therefore residents of every region by experiment, apply the approaches and measurement to contrast with these events and reduce the damage of them in their community. public attention focused on physical factor and human making envir...

Simulation of floodplain zones in Tehran's metropolitan watershed (case study: Kaan basin) Ezaatollah Ghanavati, Associate prof. Geographical science faculty, Kharzmi University Ali Ahmmadabadi. Assistance prof. Geographical science faculty, Kharzmi University Negar Gholami, MA in Geomorphology, Geographical science faculty, Kharzmi University Extended abstract Floodplains and adjacent riv...

Simulation of floodplain zones in Tehran's metropolitan watershed (case study: Kaan basin) Ezaatollah Ghanavati, Associate prof. Geographical science faculty, Kharzmi University Ali Ahmmadabadi. Assistance prof. Geographical science faculty, Kharzmi University Negar Gholami, MA in Geomorphology, Geographical science faculty, Kharzmi University Extended abstract Floodplains and adjacent riv...

Introduction: As the main source of water and life for humans and other creatures, rivers may sometimes bring about destruction and irreparable damage. Therefore, it is necessary to study the hydraulic properties of the flow and the riverbed’s area to set a safe zone for human activities around it. On the other hand, constructions built along the river’s route such as bridges, weirs, superstruc...

Journal: :جغرافیا و مخاطرات محیطی 0
زهرا گوهری محمد تاج بخش محبوبه سربازی سید ناصر نعیمی قصابیان

1. introduction the analysis of drainage networks is a powerful tool to detect recent tectonic activity and uplift, as river channels are very sensitive to changes in the parameters that control their shapes and. climate changes, tectonics and lithology affect river equilibrium conditions and hence, river geometry. a river is in dynamic equilibrium when erosion keeps pace with sedimentation and...

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