- 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, ...
The quantity added to a depth, after all other corrections to the measured depth have been made, to refer each actual depth to the reference surface for the particular region.
Industry:Earth science
The placing of control on a common coordinate system or datum. Coordination does not imply the adjustment of data to remove discrepancies. Two surveys over the same region may be coordinated by computation on the same datum, but there may remain between them discrepancies which can be removed only by correlation.
Industry:Earth science
A composite of the principal color - separations made after all corrections have been made.
Industry:Earth science
(1) In general, land belonging to the reigning sovereign. (2) Those regions, especially within the original colonial states and also within all public-land states and territories, wherein title granted by a foreign government was passed before the acquisition of sovereignty by the USA.
Industry:Earth science
(1) A number having geodetic meaning and used frequently in geodetic calculations. Examples are the numbers defining a reference ellipsoid, the length of one degree of arc at the equator of a rotational ellipsoid, the rate of rotation of the Earth, the coordinates of the origin of a geodetic network, the force of gravity at Potsdam and the stadia constant. Sets of such numbers can be found in textbooks and professional journals. (2) One of a set of numbers adopted by the International Union of Geodesy and Geophysics (IUGG), on the recommendation of the International Association of Geodesy, and recommended for general use in geodetic calculations. The general use of such a set makes it easy to compare the results of various geodetic organizations and for one organization to use the results of another. If the numbers are changed frequently, they lose their usefulness. The IUGG therefore, except in recent years, has opposed frequent changes. Geodetic constants as of 1986 are given in the Appendix.
Industry:Earth science
The extension of a curve beyond its end point and in the same direction. If the curve is circular, the continuation has the same curvature. Continuation is the extension of a curve; prolongation is the extension of a straight line.
Industry:Earth science
The density (1) a sample of water would have if it were brought adiabatically to the surface at atmospheric pressure.
Industry:Earth science
A clock in which the intervals of time are determined by reference to the frequency at which a crystalline solid (crystal) oscillates when held between the plates of a condenser in a resonant circuit. The crystal is actually a flat plate cut from a quartz crystal at such an angle to the crystal's axes as to give the least variation in frequency of oscillation. The crystal is usually cut to give a frequency of 1 Mc/s or 5 Mc/s at resonance, although other frequencies that relate better to the sidereal day or the mean solar day have been used. The resonant frequency of the quartz plate is divided down to one cycle or pulse per second by electronic circuits. A good crystal clock has a long term stability of about 1 part in 1012.
Industry:Earth science
