- Industri: Earth science
- Number of terms: 93452
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Founded in 1941, the American Congress on Surveying and Mapping (ACSM) is an international association representing the interests of professionals in surveying, mapping and communicating spatial data relating to the Earth's surface. Today, ACSM's members include more than 7,000 surveyors, ...
Clockwise, as seen from above in the Northern Hemisphere, or counterclockwise as seen from above in the Southern Hemisphere.
Industry:Earth science
A set of values (formula or tables) representing the temperature, pressure, and other characteristics of the Earth's atmosphere for a specific region or part of the year. It is derived from observations in the region or season involved and depends less on theory than does a standard atmosphere.
Industry:Earth science
Conversion of the measured length of a base line to the length of a line that is the vertical projection of the base line onto the geoid. Sometimes referred to, erroneously, as base line reduction to sea level. The correction ΔL is calculated from the formula.
Industry:Earth science
The value H<sup>B</sup><sub>N</sub> found for the orthometric elevation H <sub>N</sub> of a point P<sub>N</sub> by dividing the value of the potential function W <sub>N</sub> per unit mass at P<sub>N</sub> (considering the value of the potential function on the geoid to be 0) by an approximation 1/2(<font face = symbol>t</font><sub><font face = symbol>f</font></sub> + g <sub>N</sub>) to the average value of the acceleration of gravity between the geoid and P<sub>N</sub>. g <sub>N</sub> is the value of the acceleration at P<sub>N</sub>, <font face = symbol>t</font><sub><font face = symbol>f</font></sub> is the value of the acceleration (calculated by a standard gravity formula) on the geoid at the latitude <font face = symbol>f</font> of P<sub>N</sub>: H<sup>B</sup><sub>N</sub> = 2W <sub>N</sub>/<font face = symbol>t</font><sub><font face = symbol>f</font></sub> + g <sub>N</sub>). W <sub>N</sub> is calculated from the measured differences <font face = symbol>D</font>H <sub>n</sub> of elevation between points P<sub>n-1</sub> and P<sub>n</sub> along a route from point P<sub>o</sub> on the geoid to P<sub>N</sub>, and the measured or otherwise determine values gn of the acceleration at P<sub>n</sub>: W <sub>N</sub> = <font face = symbol>S</font> g <sub>N</sub> <font face = symbol>D</font>H <sub>n</sub>, (n = 1 to N) or, for infinitesimal separations dH between points along the route,
Industry:Earth science
The angle, measured in the orbital plane and at the center of mass of the attracting body (or at the center of mass of both bodies), from the ascending node to the orbiting object. The sum of the argument of perigee and the true anomaly.
Industry:Earth science
(1) The figure formed by extending the initial side of an angle beyond the vertex and then removing the initial side. (2) That number which is obtained by subtracting the given angle from the numerical equivalent of two right angles, e.g., Π radians, 180°, 200g or whatever units are used for the given angle.
Industry:Earth science
An amplifier which works by adding energy to the input at a frequency in resonance with the input, thus pumping in energy in the same way that the amplitude at which a pendulum oscillates can be kept constant or increased by giving a small push to the pendulum at the end of each swing.
Industry:Earth science
(1) A low ridge of earth which marks a boundary. (2) A low ridge of earth left unplowed to mark a boundary or thru carelessness.
Industry:Earth science
On a polychromatic map, the first color printed to which succeeding colors are registered.
Industry:Earth science
The point occupied by the perspective center of an aerial camera at the instant a photograph is taken.
Industry:Earth science
