- 行业: Earth science
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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, ...
A person to whom property is transferred by deed or to whom property rights are granted by a trust instrument or other document.
Industry:Earth science
Gauss's method for solving a system of linear equations, as arranged by M. Doolittle in 1878 for routinely solving such systems. Doolittle's arrangement provides an internal check on the accuracy of the calculations and is particularly suitable for hand computing by non mathematicians.
Industry:Earth science
The gradual loss of resemblance between a symbol on a map and the object represented by that symbol, as the scale of the map becomes smaller. For example, on a large-scale map, the streets of a town may be shown specifically and accurately by lines indicating the sides and widths of the streets, and the size and locations of buildings may be shown by properly placed, filled in figures. On a medium-scale map of the same region, the symbols representing individual buildings will have disappeared and streets will be represented, if shown at all, by single lines. Only the size and extent of the town as a whole may be shown. On a small scale map, the town will be represented merely by a dot or circle indicating the area or population of the town.
Industry:Earth science
(1) The sum U of the gravitational potential V<sub>g</sub> of the Earth at a point P and the rotational potential V<sub>c</sub> at the same point: U ≡ V<sub>g</sub> (= G ∫<sub>S</sub> (ρ/r)dS) + V<sub>c</sub> (= ω² p²/2) in which G is the gravitational constant, ρ the density at a point Q in the Earth, dS an element of volume S, r the distance from P to Q, p the distance from P to the axis of rotation and ω the rate of rotation of the Earth. Integration is over the entire volume S of the Earth, including the atmosphere. The gravitational potential V<sub>g</sub> is commonly denoted simply by V. In French and German literature, W is commonly used instead of U. This definition is preferred by geodesists. (2) The negative of the sum of the grav-itational potential V <sub>g</sub> and the rotational potential V <sub>c</sub>: U ≡ -(V<sub>g</sub> + V<sub>c</sub>). This definition is much used by physicists. (3) The potential energy of a unit mass relative to the geoid, numerically equal to the work which would be done in lifting the mass from the geoid to the elevation at which the mass is actually located.
Industry:Earth science
(1) The density, as a function of distance from the axis of the image, of the photograph of a linear source in object space. It is the line integral of the point spread function. The line in object space is a geometric line lying in a plane perpendicular to the optical axis of the optical system. (2) A function giving the illuminance in the image, on a plane perpendicular to the optical axis, of a linear source of light as a function of distance from the line along which the illumination is greatest. The line spread function can be derived from the point spread function by integrating the point spread function in a definite direction.
Industry:Earth science
A plan showing (a) the original contours of the ground and (b) showing, superposed, contours of the highway, subdivision or other embankment or excavation to be completed. The superposed contour lines are shown connected, at the edge of the limits set for construction, to the contour lines of the original contours.
Industry:Earth science
An object used to cast a shadow of the Sun for determining the time or astronomical north.
Industry:Earth science
Mapping of the Earth and terrestrial phenomena, in contrast to the mapping of extraterrestrial bodies.
Industry:Earth science
The following set of numbers adopted in 1967 by the International Union of Geodesy and Geophysics:<br>
Industry:Earth science