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Geodetic latitude and geocentric latitude have different definitions. Geodetic latitude is defined as the angle between the equatorial plane and the surface normal at a point on the ellipsoid, whereas geocentric latitude is defined as the angle between the equatorial plane and a radial line connecting the centre of the ellipsoid to a point on the surface (see figure).
When the key col for a peak is close to the peak itself, prominence is easily computed by hand using a topographic map. However, when the key col is far away, or when one wants to calculate the prominence of many peaks at once, software can apply surface network modeling to a digital elevation model to find exact or approximate key cols. [8] [9]
Geographical distance or geodetic distance is the distance measured along the surface of the Earth, or the shortest arch length.. The formulae in this article calculate distances between points which are defined by geographical coordinates in terms of latitude and longitude.
Enlargeable U.S. map with state and territory high points shown as red dots and low points as green squares except where low point is a shoreline. Enlargeable map of the 50 U.S. states by mean elevation. This list includes the topographic elevations of each of the 50 U.S. states, the District of Columbia, and the U.S. territories. [1]
A geoid is needed to convert the 3D position to sea-level elevation. Pressure altimeter measuring atmospheric pressure, which decreases as altitude increases. Since atmospheric pressure varies with the weather, too, a recent local measure of the pressure at a known altitude is needed to calibrate the altimeter. Stereoscopy in aerial photography.
Heightmap comes from the mathematical term 'map' and heightfield comes from the mathematical term 'vector field'. Heightmap is the more correct description because most heightfields are not a (vector) field in mathematical terms but they are always a map (in mathematical terms as well as in the visual representation).
The orthometric height (symbol H) is the vertical distance along the plumb line from a point of interest to a reference surface known as the geoid, the vertical datum that approximates mean sea level.
The DTED format for level 0, 1 and 2 is described in U.S. Military Specification Digital Terrain Elevation Data (DTED) MIL-PRF-89020B, and amongst other parameters describes the resolution for each level: Level 0 has a post spacing of approximately 900 meters. Level 1 has a post spacing of approximately 90 meters.