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Watershed Delineation
Watershed delineation is the process of identifying the boundary of a watershed, also referred to as a catchment, drainage basin, or river basin. It is an important step in many areas of environmental science, engineering, and management, for example to study flooding, aquatic habitat, or water pollution. The activity of watershed delineation is typically performed by geographers, scientists, and engineers. Historically, watershed delineation was done by hand on paper topographic maps, sometimes supplemented with field research. In the 1980s, automated methods were developed for watershed delineation with computers and electronic data, and these are now in widespread use. Computerized methods for watershed delineation use digital elevation models (DEMs), datasets that represent the height of the Earth's land surface. Computerized watershed delineation may be done using specialized hydrologic modeling software such as WMS (hydrology software), WMS, geographic information system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watershed (image Processing)
In the study of image processing, a watershed is a transformation defined on a grayscale image. The name refers metaphorically to a geological ''watershed'', or drainage divide, which separates adjacent drainage basins. The watershed transformation treats the image it operates upon like a topographic map, with the brightness of each point representing its height, and finds the lines that run along the tops of ridges. There are different technical definitions of a watershed. In graphs, watershed lines may be defined on the nodes, on the edges, or hybrid lines on both nodes and edges. Watersheds may also be defined in the continuous domain. There are also many different algorithms to compute watersheds. Watershed algorithms are used in image processing primarily for object segmentation purposes, that is, for separating different objects in an image. This allows for counting the objects or for further analysis of the separated objects. Image:Relief of gradient of heart MRI.png, Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YouTube
YouTube is an American social media and online video sharing platform owned by Google. YouTube was founded on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim who were three former employees of PayPal. Headquartered in San Bruno, California, it is the second-most-visited website in the world, after Google Search. In January 2024, YouTube had more than 2.7billion monthly active users, who collectively watched more than one billion hours of videos every day. , videos were being uploaded to the platform at a rate of more than 500 hours of content per minute, and , there were approximately 14.8billion videos in total. On November 13, 2006, YouTube was purchased by Google for $1.65 billion (equivalent to $ billion in ). Google expanded YouTube's business model of generating revenue from advertisements alone, to offering paid content such as movies and exclusive content produced by and for YouTube. It also offers YouTube Premium, a paid subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SWAT Model
SWAT (soil and water assessment tool) is a river basin scale model developed to quantify the impact of land management practices in large, complex watersheds. SWAT is a public domain software enabled model actively supported by the USDA Agricultural Research Service at theBlackland Research & Extension Centerin Temple, Texas, USA. It is a hydrology model with the following components: weather, surface runoff, return flow, percolation, evapotranspiration, transmission losses, pond and reservoir storage, crop growth and irrigation, groundwater flow, reach routing, nutrient and pesticide loading, and water transfer. SWAT can be considered a watershed hydrological transport model. This model is used worldwide and is continuously under development. As of July 2012, more than 1000 peer-reviewed articles have been published that document its various applications. Model operation SWAT is a continuous time model that operates on a daily time step at basin scale. The objective of such a mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRASS GIS
''Geographic Resources Analysis Support System'' (commonly termed ''GRASS GIS'') is a geographic information system (GIS) software suite used for geospatial data management and analysis, image processing, producing graphics and maps, spatial and temporal modeling, and visualizing. It can handle raster, topological vector, image processing, and graphic data. GRASS contains over 350 modules to render maps and images on monitor and paper; manipulate raster and vector data including vector networks; process multispectral image data; and create, manage, and store spatial data. It is licensed and released as free and open-source software under the GNU General Public License (GPL). It runs on multiple operating systems, including , Windows and Linux. Users can interface with the software features through a graphical user interface (GUI) or by ''plugging into'' GRASS via other software such as QGIS. They can also interface with the modules directly through a bespoke shell that the appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geographic Information System
A geographic information system (GIS) consists of integrated computer hardware and Geographic information system software, software that store, manage, Spatial analysis, analyze, edit, output, and Cartographic design, visualize Geographic data and information, geographic data. Much of this often happens within a spatial database; however, this is not essential to meet the definition of a GIS. In a broader sense, one may consider such a system also to include human users and support staff, procedures and workflows, the Geographic Information Science and Technology Body of Knowledge, body of knowledge of relevant concepts and methods, and institutional organizations. The uncounted plural, ''geographic information systems'', also abbreviated GIS, is the most common term for the industry and profession concerned with these systems. The academic discipline that studies these systems and their underlying geographic principles, may also be abbreviated as GIS, but the unambiguous GIScie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Braided River
A braided river (also called braided channel or braided stream) consists of a network of river channel (geography), channels separated by small, often temporary, islands called ''braid bars'' or, in British English usage, ''aits'' or ''eyots''. Braided streams tend to occur in rivers with high sediment loads or coarse grain sizes, and in rivers with steeper Stream slope, slopes than typical rivers with straight or meandering channel patterns. They are also associated with rivers with rapid and frequent variation in the amount of water they carry, i.e., with "Flash flood, flashy" rivers, and with rivers with weak River bank, banks. Braided channels are found in a variety of environments all over the world, including gravelly mountain streams, sand bed rivers, on alluvial fans, on river deltas, and across depositional plains. Description A braided river consists of a network of multiple shallow channels that diverge and rejoin around ephemeral ''braid bars''. This gives the river ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Delta
A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creation of a river delta occurs at the '' river mouth'', where the river merges into an ocean, a sea, or an estuary, into a lake, a reservoir, or (more rarely) into another river that cannot carry away the sediment supplied by the feeding river. Etymologically, the term ''river delta'' derives from the triangular shape (Δ) of the uppercase Greek letter delta. In hydrology, the dimensions of a river delta are determined by the balance between the watershed processes that supply sediment and the watershed processes that redistribute, sequester, and export the supplied sediment into the receiving basin. River deltas are important in human civilization, as they are major agricultural production centers and population centers. They can provide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DEM Conditioning Example
DEM was the ISO 4217 currency code for the Deutsche Mark, former currency of Germany Computing * Digital elevation model, a digital representation of ground-surface topography or terrain ** .dem, a common extension for USGS DEM files * Discrete element method or discrete element modeling, a family of numerical methods for computing the motion of a large number of small particles (like molecules or grains of sand) * Diffuse element method, a numerical simulation method used (for example) to solve partial differential equations * Display Encode Mode, a feature of the AMD's Video Codec Engine * Distance Estimation Method, for drawing Julia sets or Mandelbrot sets Organisations * Department of Environmental Management, a name of various government entities * Democratic Party, short form of the name of the political parties in the world * Democratic Party (United States) * Democrats (Brazil) * Dravske elektrarne Maribor d.o.o., an electric power company in Slovenia * Day E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain. The term ''RADAR'' was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term ''radar'' has since entered English and other languages as an anacronym, a common noun, losing all capitalization. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwave domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving ... [...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] |
Stereophotogrammetry
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] |
