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Digital Elevation Models
A digital elevation model (DEM) or digital surface model (DSM) is a 3D computer graphics representation of elevation data to represent terrain or overlaying objects, commonly of a planet, moon, or asteroid. A "global DEM" refers to a discrete global grid. DEMs are used often in geographic information systems (GIS), and are the most common basis for digitally produced relief maps. A digital terrain model (DTM) represents specifically the ground surface while DEM and DSM may represent tree top canopy or building roofs. While a DSM may be useful for landscape modeling, city modeling and visualization applications, a DTM is often required for flood or drainage modeling, land-use studies, geological applications, and other applications, and in planetary science. Terminology There is no universal usage of the terms ''digital elevation model'' (DEM), ''digital terrain model'' (DTM) and ''digital surface model'' (DSM) in scientific literature. In most cases the term ''digital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DTM DSM
DTM may refer to: Sport * Deutsche Tourenwagen Masters, a motor-racing series staged annually in Germany since 2000 * Deutsche Tourenwagen Meisterschaft, a motor-racing championship staged in Germany from 1984 to 1995 Computing * Data Transfer Manager, a form of autonomous peripheral operations in microcontrollers * Deterministic turing machine, an abstract symbol-manipulating device that was first described in 1936 by Alan Turing * Digital terrain model, a digital representation of ground-surface topography or terrain * Digital transaction management, a category of cloud services designed to digitally manage document-based transactions * Driver Test Manager, a test-automation framework provided by Microsoft as a part of Windows Driver Kit (WDK) * Dual Transfer Mode, supporting simultaneous voice and packet data in a GSM network * Dynamic synchronous Transfer Mode, a networking technology Medicine * Dermatophyte test medium, a specialized agar used to diagnose a fungal infection ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lidar
Lidar (, also LIDAR, an acronym of "light detection and ranging" or "laser imaging, detection, and ranging") is a method for determining ranging, ranges by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. Lidar may operate in a fixed direction (e.g., vertical) or it may scan multiple directions, in a special combination of 3-D scanning and laser scanning. Lidar has terrestrial, airborne, and mobile applications. It is commonly used to make high-resolution maps, with applications in surveying, geodesy, geomatics, archaeology, geography, geology, geomorphology, seismology, forestry, atmospheric physics, laser guidance, airborne laser swathe mapping (ALSM), and Mars Orbiter Laser Altimeter, laser altimetry. It is used to make digital 3D modeling, 3-D representations of areas on the Earth's surface and ocean bottom of the intertidal and near coastal zone by varying the wavelength of light. It has also been in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photogrammetry
Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena. While the invention of the method is attributed to Aimé Laussedat, the term "photogrammetry" was coined by the German architect , which appeared in his 1867 article "Die Photometrographie." There are many variants of photogrammetry. One example is the extraction of three-dimensional measurements from two-dimensional data (i.e. images); for example, the distance between two points that lie on a plane parallel to the photographic image plane can be determined by measuring their distance on the image, if the scale (map), scale of the image is known. Another is the extraction of accurate color ranges and values representing such quantities as albedo, specular reflection, Metallicity#Photometric colors, metallicity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangular Irregular Network
In computer graphics, a triangulated irregular network (TIN) is a representation of a continuous surface consisting entirely of triangular facets (a triangle mesh), used mainly as Discrete Global Grid in primary elevation modeling. The vertices of these triangles are created from field recorded spot elevations through a variety of means including surveying through conventional techniques, Global Positioning System Real-Time Kinematic (GPS RTK), photogrammetry, or some other means. Associated with three-dimensional data and topography, TINs are useful for the description and analysis of general horizontal distributions and relationships. Digital TIN data structures are used in a variety of applications, including geographic information systems (GIS), and computer aided design (CAD) for the visual representation of a topographical surface. A TIN is a vector-based representation of the physical land surface or sea bottom, made up of irregularly distributed nodes and lines wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heightmap
In computer graphics, a heightmap or heightfield is a raster image used mainly as Discrete Global Grid in secondary elevation modeling. Each pixel stores values, such as surface elevation data, for display in 3D computer graphics. A heightmap can be used in bump mapping to calculate where this 3D data would create shadow in a material, in displacement mapping to displace the actual geometric position of points over the textured surface, or for terrain where the heightmap is converted into a 3D mesh. A heightmap contains one channel interpreted as a distance of displacement or "height" from the "floor" of a surface and sometimes visualized as luma of a grayscale image, with black representing minimum height and white representing maximum height. When the map is rendered, the designer can specify the amount of displacement for each unit of the height channel, which corresponds to the “contrast” of the image. Heightmaps can be stored by themselves in existing graysc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raster Graphics
upright=1, The Smiley, smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Enlarging further, each pixel can be analyzed, with their colors constructed through combination of the values for red, green and blue. In computer graphics and digital photography, a raster graphic, raster image, or simply raster is a two-dimensional image or picture represented as a rectangular Matrix (mathematics), matrix or grid of pixels, viewable via a computer display, paper, or other display medium. A raster image is technically characterized by the width and height of the image in pixels and by the number of bits per pixel. Raster images are stored in image files with varying dissemination, production, generation, and acquisition formats. The printing and prepress industries know raster graphics as contones (from "continuous tones"). In contrast, '' line art'' is usually implemented as vector graphics in digital systems. Many raster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Srtm Ramp2
The Shuttle Radar Topography Mission (SRTM) is an international research effort that obtained digital elevation models on a near-global scale from 56°S to 60°N, to generate the most complete high-resolution digital topographic database of Earth prior to the release of the ASTER GDEM in 2009. SRTM consisted of a specially modified radar system that flew on board the Space Shuttle Endeavour during the 11-day STS-99 mission in February 2000. The radar system was based on the older '' Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar'' (SIR-C/X-SAR), previously used on the Shuttle in 1994. To acquire topographic data, the SRTM payload was outfitted with two radar antennas. One antenna was located in the Shuttle's payload bay, the other – a critical change from the SIR-C/X-SAR, allowing single-pass interferometry – on the end of a 60-meter (200-foot) mast that extended from the payload bay once the Shuttle was in space. The technique employed is known as interfer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SRTM
The Shuttle Radar Topography Mission (SRTM) is an international research effort that obtained digital elevation models on a near-global scale from 56th parallel south, 56°S to 60th parallel north, 60°N, to generate the most complete high-resolution digital topographic database of Earth prior to the release of the ASTER GDEM in 2009. SRTM consisted of a specially modified radar system that flew on board the Space Shuttle Endeavour during the 11-day STS-99 mission in February 2000. The radar system was based on the older ''Spaceborne Imaging Radar, Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar'' (SIR-C/X-SAR), previously used on the Shuttle in 1994. To acquire Topography, topographic data, the SRTM payload was outfitted with two radar antennas. One antenna was located in the Shuttle's payload bay, the other – a critical change from the SIR-C/X-SAR, allowing single-pass interferometry – on the end of a 60-meter (200-foot) mast that extended from the payload bay on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spot Image
Spot Image, a public limited company created in 1982 by the French Space Agency, Centre National d'Etudes Spatiales (CNES), the IGN, and Space Manufacturers (Matra, Alcatel, SSC, etc.) is a subsidiary of Airbus Defence and Space (99%). The company is the commercial operator for the SPOT Earth observation satellites. Network and partners Spot Image is a worldwide distributor of products and services using imagery from Earth observation satellites and works through a network of subsidiaries, local offices (Australia, Brazil, China, United States, Japan, Peru, Singapore), and partners. The goal is to provide on-the-spot service with worldwide availability. Spot Image works with a network of more than 30 direct receiving stations handling images acquired by the SPOT satellites. Spot Image collaborates with EU's GMES/Copernicus programme, shares geographic information with the OGC and contributes to the interoperability of web services; with Infoterra Global it continues to offe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CGIAR
CGIAR (formerly the Consultative Group for International Agricultural Research) is a global partnership that unites international organizations engaged in research about food security. CGIAR research aims to reduce rural poverty, increase food security, improve human health and nutrition, and sustainable management of natural resources. CGIAR research is carried out at 15 centers that collaborate with partners from national and regional research institutes, civil society organizations, academia, development organizations, and the private sector. These research centers are around the globe, with most in the Global South and Center of origin, Vavilov Centers of agricultural crop genetic diversity. CGIAR has an annual research portfolio of just over US$900 million with more than 9,000 staff working in 89 countries. Funding is provided by national governments, multilateral funding and development agencies and leading private foundations. Representatives of CGIAR Funders and develo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advanced Spaceborne Thermal Emission And Reflection Radiometer
The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a Japanese remote sensing instrument onboard the Terra satellite launched by NASA in 1999. It has been collecting data since February 2000. ASTER provides high-resolution images of Earth in 14 different bands of the electromagnetic spectrum, ranging from visible to thermal infrared light. The resolution of images ranges between 15 and 90 meters. ASTER data is used to create detailed maps of surface temperature of land, emissivity, reflectance, and elevation. In April 2008, the SWIR detectors of ASTER began malfunctioning and were publicly declared non-operational by NASA in January 2009. All SWIR data collected after 1 April 2008 has been marked as unusable. The ASTER Global Digital Elevation Model (GDEM) is available at no charge to users worldwide via electronic download. As of 2 April 2016, the entire catalogue of ASTER image data became publicly available online at no cost. It can be downlo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
