Viewshed Analysis
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Viewshed Analysis
Viewshed analysis is a computational algorithm that delineates a viewshed, the area that is visible (on the base terrain surface) from a given location. It is a common part of the terrain analysis toolset found in of most geographic information system (GIS) software. The analysis uses the elevation value of each cell of the digital elevation model (DEM) to determine visibility to or from a particular cell. The location of this particular cell varies depending on the needs of the analysis. For example, a viewshed analysis is commonly used to locate communication towers or determining the view from a road. Viewsheds can be calculated using an individual point such as a tower or multiple points such as a line representing a road. When analyzing a line segment, each of the vertices along the line is calculated to determine its visible area. The process can also be reversed. For example, when locating a landfill, the analysis can determine from where the landfill is visible to keep it ...
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Viewshed
A viewshed is the geographical area that is visible from a location. It includes all surrounding points that are in line-of-sight with that location and excludes points that are beyond the horizon or obstructed by terrain and other features (e.g., buildings, trees). Conversely, it can also refer to area from which an object can be seen. A viewshed is not necessarily "visible" to humans; the same concept is used in radio communications to indicate where a specific combination of transmitter, antenna, and terrain allow reception of signal. Viewsheds are commonly used in terrain analysis, which is of interest to urban planning, archaeology, and military science. In urban planning, for example, viewsheds tend to be calculated for areas of particular scenic or historic value that are deemed worthy of preservation against development or other change. Viewsheds are often calculated for public areas — for example, from public roadways, public parks, or high-rise buildings. The preserva ...
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Azimuth
An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematically, the relative position vector from an observer (origin) to a point of interest is projected perpendicularly onto a reference plane (the horizontal plane); the angle between the projected vector and a reference vector on the reference plane is called the azimuth. When used as a celestial coordinate, the azimuth is the horizontal direction of a star or other astronomical object in the sky. The star is the point of interest, the reference plane is the local area (e.g. a circular area with a 5 km radius at sea level) around an observer on Earth's surface, and the reference vector points to true north. The azimuth is the angle between the north vector and the star's vector on the horizontal plane. Azimuth is usually measured in d ...
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Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terrestrial planet with a thin atmosphere (less than 1% that of Earth's), and has a crust primarily composed of elements similar to Earth's crust, as well as a core made of iron and nickel. Mars has surface features such as impact craters, valleys, dunes and polar ice caps. It has two small and irregularly shaped moons, Phobos (moon), Phobos and Deimos (moon), Deimos. Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and List of tallest mountains in the Solar System, highest known mountain in the Solar System and Valles Marineris, one of the largest canyons in the Solar System. The North Polar Basin (Mars), Borealis basin in the Northern Hemisphere covers approximately 40% of the planet and may be a la ...
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Mars Exploration Rover
NASA's Mars Exploration Rover (MER) mission was a robotic space mission involving two Mars rovers, ''Spirit (rover), Spirit'' and ''Opportunity (rover), Opportunity'', exploring the planet Mars. It began in 2003 with the launch of the two rover (space exploration), rovers to explore the Martian surface and Geology of Mars, geology; both landed on Mars at separate locations in January 2004. Both rovers far outlived their planned missions of 90 Timekeeping on Mars#Sols, Martian solar days: MER-A ''Spirit'' was active until March 22, 2010, while MER-B ''Opportunity'' was active until June 10, 2018. Objectives The mission's scientific objective was to search for and characterize a wide range of rock (geology), rocks and soils that hold clues to past Water on Mars, water activity on Mars. The mission is part of NASA's Mars Exploration Program, which includes three previous successful landers: the two Viking program landers in 1976 and Mars Pathfinder probe in 1997. The total cost o ...
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NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown management f ...
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United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredt ...
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Mars Viewshed
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmosphere (less than 1% that of Earth's), and has a crust primarily composed of elements similar to Earth's crust, as well as a core made of iron and nickel. Mars has surface features such as impact craters, valleys, dunes and polar ice caps. It has two small and irregularly shaped moons, Phobos and Deimos. Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and highest known mountain in the Solar System and Valles Marineris, one of the largest canyons in the Solar System. The Borealis basin in the Northern Hemisphere covers approximately 40% of the planet and may be a large impact feature. Days and seasons on Mars are comparable to those of Earth, as the planets have a similar rotation period and tilt ...
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National Historic Trail
The National Trails System is a series of trails in the United States designated "to promote the preservation of, public access to, travel within, and enjoyment and appreciation of the open-air, outdoor areas and historic resources of the Nation". There are four types of trails: the national scenic trails, national historic trails, national recreation trails, and connecting or side trails. The national trails provide opportunities for hiking and historic education, as well as horseback riding, biking, camping, scenic driving, water sports, and other activities. The National Trails System consists of 11 national scenic trails, 19 national historic trails, over 1,300 national recreation trails, and seven connecting and side trails, as well as one national geologic trail, with a total length of more than . The scenic and historic trails are in every state, and Virginia and Wyoming have the most running through them, with six. In response to a call by President Lyndon B. Johnson ...
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Bureau Of Land Management
The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands. Headquartered in Washington DC, and with oversight over , it governs one eighth of the country's landmass. President Harry S. Truman created the BLM in 1946 by combining two existing agencies: the General Land Office and the Grazing Service. The agency manages the federal government's nearly of subsurface mineral estate located beneath federal, state and private lands severed from their surface rights by the Homestead Act of 1862. Most BLM public lands are located in these 12 western states: Alaska, Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming. The mission of the BLM is "to sustain the health, diversity, and productivity of the public lands for the use and enjoyment of present and future generations." Originally BLM holdings were described as "land nobody wanted" because home ...
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Wyoming
Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the south. With a population of 576,851 in the 2020 United States census, Wyoming is the List of U.S. states and territories by population, least populous state despite being the List of U.S. states and territories by area, 10th largest by area, with the List of U.S. states by population density, second-lowest population density after Alaska. The state capital and List of municipalities in Wyoming, most populous city is Cheyenne, Wyoming, Cheyenne, which had an estimated population of 63,957 in 2018. Wyoming's western half is covered mostly by the ranges and rangelands of the Rocky Mountains, while the eastern half of the state is high-elevation prairie called the High Plains (United States), High Plains. It is drier ...
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Rock Springs, Wyoming
Rock Springs is a city in Sweetwater County, Wyoming, United States. The population was 23,036 at the 2010 census, making it the fifth most populated city in the state of Wyoming, and the most populous city in Sweetwater County. Rock Springs is the principal city of the Rock Springs micropolitan statistical area, which has a population of 37,975. Rock Springs is known as the Home of 56 Nationalities because of the influx of immigrants from all over the world who came to work in the coal mines that supplied the fuel to power the steam engines of the Union Pacific Railroad. The city's rich cultural heritage is celebrated each summer on International Day, a festival where the foods, costumes, and traditions of residents' ancestors are recreated and enjoyed at Bunning Park in downtown Rock Springs. Rock Springs is the site of Western Wyoming Community College and Wyoming's Big Show, a yearly event with a carnival and concerts which is held at the Sweetwater County Events Complex. ...
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Fire Lookout Tower
A fire lookout tower, fire tower or lookout tower, provides housing and protection for a person known as a "fire lookout" whose duty it is to search for wildfires in the wilderness. It is a small building, usually on the summit of a mountain or other high vantage point, to maximize viewing distance and range, known as ''view shed''. From this vantage point the fire lookout can see smoke that may develop, determine the location by using a device known as an ''Osborne Fire Finder'', and call fire suppression personnel to the fire. Lookouts also report weather changes and plot the location of lightning strikes during storms. The location of the strike is monitored for a period of days afterwards, in case of ignition. A typical fire lookout tower consists of a small room, known as a ''cab,'' atop a large steel or wooden tower. Historically, the tops of tall trees have also been used to mount permanent platforms. Sometimes natural rock may be used to create a lower platform. In cases ...
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