نتایج جستجو برای: مدلهای ارتفاعی رقومی dems

تعداد نتایج: 10365  

2007
Robert H. Erskine Timothy R. Green Jorge A. Ramirez

Terrain attributes are commonly used to explain the spatial variability of agronomic, pedologic, and hydrologic variables. The terrain attributes studied here (elevation, slope, aspect, and curvature) are estimated readily from digital elevation models (DEMs), but questions remain about how the accuracy and sample spacing of the elevation data affect the estimated attributes. The main objective...

2007
J. Vaze J. Teng

Digital Elevation Models (DEMs) are the digital representation of natural topographic as well as man-made features located on the surface of the earth. For the last few decades, DEMs are widely used for resource management, urban planning, transportation planning, earth sciences, environmental assessments, and Geographic Information System (GIS) applications. The hydrologic community is also mo...

ژورنال: :علوم و فناوری دریا 0

در این تحقیق از خاصیت تکرار شوندگی زمانی مشاهدات ماهواره ارتفاع سنجی توپکس پوزایدون برای ایجاد سری های زمانی در پای حرکت ماهواره در دریای عمان و خلیج فارس استفاده شد. برای این منظور بر هر نقطه مکانی یک سری زمانی ایجاد گردید. سپس با استفاده از روش کمترین مربعات قسمت خطی آن به عنوان برآورد سطح متوسط دریا و بخش وابسته به زمان آن به عنوان تغییرات زمانی سطح متوسط دریا آنالیز گردید. نظر به اهمیت تعیی...

2017
Yaqing Chen Dan Liu Pengfei Liu Yajing Chen Huiling Yu Quan Zhang

The present study aimed to identify potential therapeutic targets of intrahepatic cholangiocarcinoma (ICC) via integrated analysis of gene (transcript version) and microRNA (miRNA/miR) expression. The miRNA microarray dataset GSE32957 contained miRNA expression data from 16 ICC, 7 mixed type of combined hepatocellular‑cholangiocarcinoma (CHC), 2 hepatic adenoma, 3 focal nodular hyperplasia (FNH...

ژورنال: :جغرافیا و توسعه 0
محمدرضا ثروتی مژگان رستمی کاظم نصرتی محمود احمدی

در پژوهش حاضر، عوامل کنترل کننده ی فروچاله ها به همراه مورفومتری آنها با تکیه برفروچاله ها مطالعه شده است. فروچاله ها اشکال غالب منطقه گازورخانی کرمانشاه را تشکیل می دهند. اولین قدم در شناخت و چگونگی گسترش پدیده کارست و به ویژه عوامل کنترل کننده ی فروچاله ها در منطقه ی مورد مطالعه مورفومتری (ریخت سنجی) آنهاست. در این پژوهش طیّ بازدید میدانی، آنالیز نقشه های توپوگرافی رقومی 1:25000 و مدل رقومی ار...

1998
J. Bryan Mercer Scott Thornton Keith Tennant

In this paper we report upon the advances achieved over the past year in the creation of Digital Elevation Models (DEMs) on an operational, commercial basis, using data from two very different radar platforms. STAR3i is an airborne interferometric Synthetic Aperture Radar (SAR), capable of achieving DEMs at a level of detail and accuracy suitable for map scales as large as 1:10,000. A less deta...

2012
Istvan Elek Janos Roden Thai Binh Nguyen

The aim of this paper is to introduce the principles of the evolution units, which are named the digital evolutionary machines. The entities will be constructed based on these principles. Their properties and abilities will be shown with some experimental results. The knowledge base of DEMs was stored in a database, which is the source of the individual knowledge graph. It helps to make decisio...

2003
M. Gelautz P. Paillou C. W. Chen H. A. Zebker

In this experiment, we derive and compare radar stereo and interferometric elevation models (DEMs) of a study site in Djibouti, East Africa. As test data, we use a Radarsat stereo pair and ERS-2 and Radarsat interferometric data. Comparison of the reconstructed DEMs with a SPOT reference DEM shows that in regions of high coherence the DEMs produced by interferometry are of much better quality t...

2012
Weiling Guo Qinke Yang Haijiang Wang Rui Li

In the same area, the terrain details described by DEM are gradually generalized and primary terrain features are only retained in the coarser-resolution DEM. In this paper, wavelet multiresolution analysis and Radical Law selection principles were combined to model the terrain generalizing processes and derive three different scale-parameter DEMs based on DEM data generated by large-scale digi...

1999
J. Bryan Mercer Steven Schnick

Within the past few years there has been a significant increase in the use of Digital Elevation Models (DEMs), for applications as varied as telecommunications and precision agriculture, forestry and flood-risk assessment. Additionally, one may expect that externally-supplied DEMs will be used increasingly for ortho-rectification of high-resolution satellite imagery as it becomes available. The...

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