- 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, ...
An easement precluding the owner of the land upon which the easement exists from acting on the land in a way one would be entitled to act if no easement existed.
Industry:Earth science
The Gaussian method of solving a set of simultaneous linear equations by successively solving for each unknown in terms of the others and then substituting this solution into the remaining equations, as organized by Doolittle for greater ease of computation for easier checking of the computations. It is also called the Gauss Doolittle method, which may be preferable because Gauss invented the basic method.
Industry:Earth science
Determining the distance from the surface of a body of water to the bottom by measuring the interval of time it takes a sonic pulse to travel from the surface to the bottom and back again. The principal source of error is incomplete correction for refraction; another is schools of fish which reflect the sonic pulses before the pulses reach the bottom. The idea of echo sounding was suggested by D. Arago in 1807. Eels, in a U. S. patent of 1907, described the principles completely. The first echo sounder known to be used successfully was designed by A. Behm a few years later.
Industry:Earth science
(1) A quantity e indicating the amount by which a given conic section differs from a circle, and given by the formula e ≡ ( √ (a - k² (b/a)²), in which a is half the length of the major axis, b half the length of the minor axis and k² a constant equal to +1 for an ellipse, 0 for a parabola and 1 for a hyperbola. It is also called the first eccentricity when it must be distinguished from the second eccentricity. (2) The eccentricity of a surface is the eccentricity (definition 1) of a designated intersection of that surface with a plane. In particular, (a) The eccentricity of a rotational ellipsoid (spheroid) is the eccentricity of an ellipse formed by meridional section of the spheroid. (b) An ellipsoid has in general two eccentricities: the meridional eccentricity, which is the eccentricity of the ellipse formed by a section containing the longest and the shortest axes (one of which is the polar axis), and the equatorial eccentricity, which is the eccentricity of the ellipse formed by a section through the center and perpendicular to the polar axis. (c) The eccentricity of a rotational ellipsoid (spheroid), is given by + √ ( (a² +b²) / a²), in which a and b are the lengths of the equatorial and polar semi axes, respectively. (3) The distance of a point from a center or axis. The term is generally applied either to (a) the distance of a surveying instrument from the point it should be occupying or to (b) the rotation of a part of the instrument about an axis other than the proper axis.
Industry:Earth science
The pattern, or overall appearance, made by the network of drainage features on a map or chart.
Industry:Earth science
The Earth considered as a fluid in hydrostatic equilibrium (under gravitational and centrifugal forces).
Industry:Earth science
An eclipse in which the Moon passes through the shadow cast by the Earth. The eclipse may be total (the Moon passing completely into the Earth's umbra), partial (the Moon passing partially into the Earth's umbra at the time of greatest eclipse) or penumbral (the Moon passing only through the Earth's penumbra).
Industry:Earth science
Une éclipse dans laquelle la Lune passe au travers l'ombre projetée par la Terre. L'éclipse peut être totale (la Lune passant complètement dans l'ombre de la Terre), partielle (la Lune passant partiellement dans l'ombre de la Terre au moment de la plus grande éclipse) ou de pénombre (la Lune passant uniquement au travers de la pénombre de la Terre).
Industry:Earth science
Une éclipse dans laquelle la Lune passe au travers l'ombre projetée par la Terre. L'éclipse peut être totale (la Lune passant complètement dans l'ombre de la Terre), partielle (la Lune passant partiellement dans l'ombre de la Terre au moment de la plus grande éclipse) ou de pénombre (la Lune passant uniquement au travers de la pénombre de la Terre).
Industry:Earth science
The actual ecliptic at a specified instant. The term distinguishes this concept from that of a mathematically derived ecliptic such as an average ecliptic. It has the defect that the ecliptic is itself a mathematical concept.
Industry:Earth science
