- 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, ...
A material prepared by acetylation of cellulose. Cellulose acetate is widely used, as transparent sheets of plastic, as a base for photographic film, in which form it is also called acetate film. It burns very slowly, in contrast to the nitrated cellulose (nitrate film) used previously.
Industry:Earth science
A gravity correction δg <sub>Bs</sub>, given by δg <sub>Bs</sub> ≡ (4π ρ G/3)((R+h) - R3/(R+h)²), which is the gravity caused by a spherical shell, density ρ, inner radius R and thickness h. G is the gravitational constant. The radius R is usually chosen to be the average radius of the Earth, although it is more properly chosen so that the outer surface passes through the point of measurement, P at an elevation H = h. This gravity correction is frequently used instead of the Bouguer gravity correction, leading to the spherical Bouguer gravity anomaly instead of the Bouguer gravity anomaly.
Industry:Earth science
A map prepared specifically for delineating a boundary line and adjacent territory.
Industry:Earth science
A major road into which other streets and roads feed their traffic and from which other streets and roads receive their traffic. It is generally shorter than a highway, occurs in cities, and usually serves thru traffic on a continuous route. It often has a median strip or traffic islands.
Industry:Earth science
A bench mark connected to the reference surface by continuous second order leveling or by a continuous combination of first order and second order leveling.
Industry:Earth science
(1) A printing plate having both halftone and line work on its surface. (2) A printing plate having images of two or more objects on its surface.
Industry:Earth science
The statement that the antisymmetric first covariant derivative of the Riemann tensor vanishes identically.
Industry:Earth science
An artificial reservoir or tank designed for storing rain-water collected from a roof.
Industry:Earth science
A pendulum apparatus constructed in 1926 by Lennox Coyningham and consisting of three synchronous pendulums of the Sterneck type, made of invar, with knife edges of stellite resting on plates of agate. Any two of the pendulums are swung simultaneously in opposite directions. Two Cambridge pendulum apparati have been made. They were designed to be able to measure gravity acceleration to a precision of about 0. 2 mgal. Both were used extensively in measuring the intensity of gravity for the International Gravity Standardization Net 1971.
Industry:Earth science
