- Industry: 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, ...
An atomic clock in which the characteristic frequency of 9 192 631 770 cycles per second of the cesium atom is used to determine the basic time interval for the clock. Because the second is defined by international agreement as the length of time needed for this number of cycles to occur, time intervals given by a cesium clock operating under the conditions specified by the definition have zero error. A cesium clock is therefore used whenever the highest possible accuracy over long intervals is needed. However, over short intervals, the frequency may vary appreciably and clocks with better stability over short intervals may be used to give time over such intervals. Cesium clocks are then used to monitor the time over longer intervals.
Industry:Earth science
A method for creating all colors by adding various intensities of lights of the three primary colors (red, green, blue). The lights are produced by three projectors each provided with a filter that transmits only one of the primary colors.
Industry:Earth science
A measuring engine having a separate eyepiece for each eye but a common objective lens system. A binocular comparator allows both eyes to see the object (e.g., a photograph) under study, but does not provide a stereoscopic view of the object.
Industry:Earth science
A region classified according to the kinds of plants and animals living there. Types used as standard by the U. S. Bureau of Land Management are: tundra, boreal forest, coniferous forest, woodland brushland, grassland and desert.
Industry:Earth science
(1) A quantity of land of variable size, depending on the locality. (2) An allotment of land given to a horse soldier as a result of conquest.
Industry:Earth science
A chart of which the chief feature is isoclinic lines each for a different value of the magnetic inclination along the corresponding line on the Earth.
Industry:Earth science
The quantity δg <sub>Bc</sub> (≡ 2πGh² ρ/2a) representing the force per unit mass, or acceleration, caused by the attraction of a cylindrical solid of density ρ, radius a and height h on a unit mass located at the intersection of the cylinder's axis with the top surface. G is the gravitational constant. The cylindrical Bouguer gravity correction is used in calculating Faye's gravity anomaly.
Industry:Earth science
A diagram made by plotting any one of the chromaticity coordinates against another.
Industry:Earth science
(1) A great circle as one of the reference figures for the origin of a coordinate system. (2) In particular, such a circle 90<sup>o</sup> from the poles of a spherical-coordinate system, such as the Equator.
Industry:Earth science
