- 行业: 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, ...
(1) The length of a bronze bar, a copy of the Imperial Standard Yard bar A, at 61. 9l<sup>o</sup>F. This standard served from 1874 to 1951. (2) 0. 9144 of the International Meter. This is the official redefinition of 1951.
Industry:Earth science
That part of the Doppler effect which depends on the direction of the relative velocity between the source and the observer. It is the analog, for an electromagnetic wave, of the Doppler effect in sound.
Industry:Earth science
An elongated hill or ridge composed of till, usually oval and shaped like half an egg.
Industry:Earth science
The right to use the space at a designated distance above the surface of the land e.g., for power lines, aviation and air rights.
Industry:Earth science
In cartography, all features associated with water, such as shorelines, rivers, lakes, marshes, etc.
Industry:Earth science
An instrument used in magnetic surveys for determining the magnetic dip; it works on the principle of a small dynamo whose magnetic field is provided by the Earth. The current generated by the dynamo is sent to a galvanometer which indicates the amount of dip.
Industry:Earth science
A number, also called an argument number, identifying a particular component of the tides, according to a scheme devised by Doodson. In the equation for the amplitude of the tide (atmospheric, oceanic, or earth) as a function of time, the trigonometric series used contains as argument a linear function aτ + bs + ch + dp + eN' + fps, in which b,c,d,e,f are integers lying between -4 and +4, and a takes on only positive values and 0. τ is local mean lunar time; s is the mean longitude of the Moon's orbit; h is the mean longitude of the Sun; p is the longitude of lunar perigee; N' is the negative of the mean longitude of the Moon's ascending node; and ps is the mean longitude of perihelion. A particular term is therefore identified by the coefficients a,b,c,d,e,f in the argument. The Doodson number is the number aBC. DEF, where B ≡ (b+5), C ≡ (c+5), D ≡ (d+5), E ≡ (e+5), F ≡ (f +5). For example, the M2 component, the semidiurnal tide caused by the Moon, has the Doodson number 255. 555; the S2 term has the Doodson number 273. 555; and so on. A few tidal components may have values of b or c greater than 4 in absolute value. Various conventions are used to deal with these rare cases.
Industry:Earth science
The voluntary conveyance of private property to public ownership and use, without compensation to the owner.
Industry:Earth science
That portion of, or interest in, the real estate of a deceased husband which the law gives to his widow for life. The extent varies with statutory provisions.
Industry:Earth science
Location determined using measurements of the Doppler shift in radio signals emitted by artificial satellites.
Industry:Earth science
