نتایج جستجو برای: digital terrain model

تعداد نتایج: 2369560  

1997
Marc J. van Kreveld

Digital elevation models can represent many types of geographic data. One of the common digital elevation models is the triangulated irregular network (also called TIN, or polyhedral terrain, or triangulated terrain). We discuss ways to represent a TIN in a data structure, and give some of the basic algorithms that work on TINs. These include retrieving contour lines, computing perspective view...

2000
John P. Wilson John C. Gallant

The development and application of the TAPES: Terrain Analysis Programs for the Environmental Sciences software tools described in this book was motivated by our view of the world as a stage on which a series of hierarchically scaled biophysical processes are played out (Figure 1.1). This approach is useful because it can handle the complexity of individual landscape processes and patterns as w...

2011
Helen Jenny Bernhard Jenny William E. Cartwright Lorenz Hurni

Painters of panoramic landscape maps use specific manual techniques to solve problems of occlusion, foreshortening and unfavourable orientation of landscape elements to the map viewer. Using digital means, the painters’ techniques may be translated into geometry deformation algorithms for digital panorama creation. This article explores the advantages and the suitability of applying local geome...

Journal: :Cartographica 2010
Anna M. Leonowicz Bernhard Jenny Lorenz Hurni

Shaded relief derived automatically from digital elevation models differs distinctly from traditional manual shading. Particularly at small scales, many small topographic details that are present in terrain models disturb the clear portrayal of the main relief features. Automatic shading is therefore not appropriate for high-quality cartographic products. This paper proposes a new method of gen...

2002
M. A. Brovelli M. Cannata

Lidar techniques represent a new and fruitful approach in the determination of digital surface models. One of the goals in processing this data is to set up filtering methods allowing to automatically extract the ground and the features (buildings, vegetation,...) superimposed on the terrain itself. In our work the emphasis is posed on the first topic. The method implemented took advantage of t...

2004
M. Rahnemoonfar

Digital surface representation from a set of three-dimensional samples is an important issue of computer graphics that has applications in different areas of study such as engineering, geology, geography, meteorology, medicine, etc. The digital model allows important information to be stored and analyzed without the necessity of working directly with the real surface. In addition, we can integr...

1999
Adrian R. Pearce Terry Caelli Sabrina Sestito Simon Goss Mario Selvestrel Graeme Murray

This report investigates the application of two Computer Vision techniques for characterizing critical regions in digital terrain maps: Skeletonization and Topographical Region Detection. The Navigation Path Planning problem involves nding the optimal path through a digital terrain Map and must minimize a cost function while satisfying the constraints of navigation. This process is computationa...

Journal: :international journal of environmental research 2012
m.f. yassin m. al-harbi

to enhance the understanding of the impact of obstacle buildings on pollution transportationand dispersion in the atmospheric boundary layer, it is necessary to know the atmospheric flow characteristics over terrains. wind flow characteristics in a boundary layer over a step-shaped cliff topography model with rough and smooth surfaces were studied numerically using computational fluid dynamics ...

ژورنال: فیزیک زمین و فضا 2007
عباسعلی جمعه گی عبدالرضا صفری علیرضا آزموده اردلان

محاسبة اثر جرم‌های توپوگرافی در فاصلة نزدیک، یکی از مراحل اساسی در محاسبات تعیین ژئوئید است. برای عملی ساختن این محاسبات، به شناخت توپوگرافی در قالب یک مدل رقومی زمین ((DTM) Digital Terrain Model) نیاز است. توپوگرافی امروزه به‌صورت مدل‌های رقومی با توان تفکیک (spatial resolution)، دقت و صحت‌های متفاوت بیان می‌شود. در این مقاله هدف، بررسی اثر مدل رقومی بر محاسبات تعیین ژئوئید است. برای این منظور...

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