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In meteorology, visibility is the measure of the distance at which an object or light can be clearly discerned. ... (C V = 0.02) is used to calculate visual range.
In geometry, visibility is a mathematical abstraction of the real-life notion of visibility. Given a set of obstacles in the Euclidean space , two points in the space are said to be visible to each other, if the line segment that joins them does not intersect any obstacles.
A pilot's view of Lisbon Airport's runway 21 in fog; runway visual range is about 200 m (660 ft). In aviation, the runway visual range (RVR) is the distance over which a pilot of an aircraft on the centreline of the runway can see the runway surface markings delineating the runway or the lights delineating the runway or identifying its centre line.
Prevailing visibility in aviation is a measurement of the greatest distance visible throughout at least half of the horizon, not necessarily continuously. To take the prevailing visibility, controllers reference a number of visual reference points: usually buildings , hills , or other geographic features.
To determine the visibility of a target cell, each cell between the viewpoint cell and target cell is examined for line of sight. Where cells of higher value are between the viewpoint and target cells the line of sight is blocked. If the line of sight is blocked then the target cell is determined to not be part of the viewshed.
In a transmissometer the extinction coefficient is determined by measuring direct light transmissivity, and the extinction coefficient is then used to calculate visibility range. [ 2 ] Atmospheric extinction is a wavelength dependent phenomenon, but the most common wavelength in use for transmissometers is 550 nm , which is in the middle of the ...
To calculate the radar cross-section of such a stealth body, one would typically do one-dimensional reflection calculations to calculate the surface impedance, then two dimensional numerical calculations to calculate the diffraction coefficients of edges and small three dimensional calculations to calculate the diffraction coefficients of ...
The radar horizon is a critical area of performance for aircraft detection systems, defined by the distance at which the radar beam rises enough above the Earth's surface to make detection of a target at the lowest level possible.