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A height finder radar is a type of 2-dimensional radar that measures altitude of a target. The operator slews the antenna toward a desired bearing , identifies a target echo at a desired range on the range height indicator display, then bisects the target with a cursor that is scaled to indicate the approximate altitude of the target. [ 7 ]
It took some time for the changed definition — Liverpool to Newlyn — to work through the system: by 1950, some 40% of the lower secondary and tertiary levellings were still using the Liverpool datum. But following the Third Geodetic Levelling, Ordnance Survey maps published since March 1956 give spot heights above the Newlyn datum. [4] [5]
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 position and height of each benchmark are shown on large-scale maps. The terms "height" and "elevation" are often used interchangeably, but in many jurisdictions, they have specific meanings; "height" commonly refers to a local or relative difference in the vertical (such as the height of a building), whereas "elevation" refers to the ...
A spot height is an exact point on a map with an elevation recorded beside it that represents its height above a given datum. [1] In the UK this is the Ordnance Datum . Unlike a bench-mark , which is marked by a disc or plate, there is no official indication of a spot height on the ground although, in open country, spot heights may sometimes be ...
Dynamic measurements of the road profile are done with vehicle mounted instruments. The approach consisted of a sensor (initially ultrasonic but later laser) which measures the height of the vehicle relative to the road. An accelerometer is double integrated to give the height of the sensor relative to datum.
The various features shown on the map are represented by conventional signs or symbols. For example, colors can be used to indicate a classification of roads. These signs are usually explained in the margin of the map, or on a separately published characteristic sheet. [17] [18] [19] Topographic maps are also commonly called contour maps or ...
A topographical map is the main type of map used to depict elevation, often through contour lines. In a Geographic Information System (GIS), digital elevation models (DEM) are commonly used to represent the surface (topography) of a place, through a raster (grid) dataset of elevations. Digital terrain models are another way to represent terrain ...