- 行业: Earth science
- Number of terms: 93452
- Number of blossaries: 0
- Company Profile:
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) A compass that uses a gyroscope to smooth the indications of directions obtained from magnetically sensitive components. i.e., a magnetic compass with a gyroscope added to smooth the readings. (2) A gyroscopic compass so aligned, by applying torques derived from components detecting the Earth's magnetic field, that the zero point of the azimuth scale is kept on the magnetic meridian.
Industry:Earth science
The formula τ = τ<sub>o</sub>(1 2h/a+ ρ'h/(2a ρ)) for the value of gravity at a height h above the surface of reference, τ<sub>o</sub> being the value of gravity on the surface, a the radius of a spherical body with mass equal to the Earth's, ρ the average density of the Earth and ρ' the density of material between the surface and height h.
Industry:Earth science
(1) The ratio of the angle of refraction at the point of observation to the angle, at the center of the Earth, subtended between the point of observation and the point observed. (2) The ratio of the average radius of curvature of the Earth to the average radius of curvature of the path of the electromagnetic ray. (3) Half the ratio specified in definition (2).
Industry:Earth science
One of a set of certain selected stars, in the vicinity of the celestial equator, whose right ascensions are accurately known and which are used for the exact determination of longitude or of time.
Industry:Earth science
The quantity added algebraically to the time shown by a clock to obtain the correct time at a given meridian. If the clock is slow, the correction is positive; if it is fast, the correction is negative.
Industry:Earth science
The numerical statement of the limits in Chauvenet's rule.
Industry:Earth science
The core of the Earth, composed of dense material and making up most of its mass.
Industry:Earth science
The horizontal line tangent to the upper surface of the centered bubble, in a spirit level, which lies in the vertical plane through the longitudinal axis of the vial.
Industry:Earth science
A topographic map of the bed of the ocean or other body of water. Bathymetric charts usually indicate depths by contour lines, with meaningfully tinted zones between curves. They are designed especially for geophysical (oceanographic) studies, but are also useful for navigation.
Industry:Earth science
