- 行业: Earth science
- Number of terms: 93452
- Number of blossaries: 0
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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 mass of gabbroic material, approximately 5 kilometers thick, which lies under the bottom of the ocean and which may be more or less continuous beneath the continental crust.
Industry:Earth science
A course measured relative to a moving object such as a moving craft.
Industry:Earth science
The definitions of a geodetic datum by accepting the astronomically determined coordinates of the origin and the azimuth to one other station without any correction.
Industry:Earth science
(1) The quantity (A+Bμ/(1+μ))/H, in which μ is the ratio of the mass of the Moon to the mass of the Earth, H is the dynamical ellipticity of the Earth, and A and B are functions of the orbital elements of the Earth and of the ratio of the mass of the Sun to the combined masses of Earth and Moon. (2) The rate of motion of the general precession in longitude. Use of this meaning is discouraged.
Industry:Earth science
The uniform depth to which water would cover the Earth if the solid surface were smoothed off and parallel to the geoid.
Industry:Earth science
A stereoscope of simple design for tracing contour lines from stereoscopic pairs of photographs. It does not compensate for changes of scale resulting from differences of elevation or from tilt in the optical axis of the camera.
Industry:Earth science
Of a surface, able to be flattened into a flat surface without compressing or stretching.
Industry:Earth science
(1) A mathematical surface and a function, ρ, defined at each point of the surface, whose values have the dimensions (mass per unit area). The surface is called a single layer surface if it is considered one sided. It is called a double layer surface if it is considered two sided and if at each point the value + ρ is associated with one side and - ρ with the other. The solution to Poisson's differential equation can be expressed as the sum of the potentials from three distributions of density: a distribution on a single layer surface, a distribution on a double layer surface, and a distribution throughout the volume. (2) A mathematical surface and a function ρ, defined at each point of the surface, whose values are (δΦ/δn)/4π (single layer surface density) or Φ/4π (double layer surface density). Φ is a function twice differentiable in the entire space and continuously differentiable on the surface and (δ/δn) denotes the gradient of Φ at the surface.
Industry:Earth science
A yard, courtyard, or piece of ground, included within the fence surrounding a dwelling house.
Industry:Earth science
