- 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 average level of the lower of two successive low waters. It is frequently specified as the average during a particular part of the month or year, for example, mean lower low water springs, mean lower low water at spring tide near the solstices, etc.
Industry:Earth science
A correction applied to an assumed or calculated location or component thereof to allow for apparent acceleration caused by the Coriolis force.
Industry:Earth science
(1) A corner where there are no remaining traces of the monument or its accessories but whose location has been perpetuated. (2) A corner which may be recovered beyond reasonable doubt, by the testimony of the interested landowners, competent surveyors or other qualified local authorities or witnesses or by some acceptable recorded evidence. (This definition is undesirable because it applies also to corners for which the monuments or other physical evidence still exist. ) A location which depends upon the use of collateral evidence for verification can be accepted only insofar as it is supported, generally through proper relation to known corners and agreement with the field notes on distances to natural objects, stream crossings, line trees and off line blazes, etc. , or unquestionable testimony.
Industry:Earth science
The lowest layer of the ionosphere, at a distance of 70 - 80 km above the Earth's surface. It exists only during the daytime.
Industry:Earth science
A coordinate system with coordinates (u,v) such that, in the first fundamental form for the element ds of length, ds² = E du² + F du dv + g dv², the conditions E = G and F = 0 are satisfied.
Industry:Earth science
The current which is a function of the dynamic slope of an isobaric surface and which is deter-mined from an assumed layer of no motion. The current flows along the contours of dynamic topography; the speed is inversely proportional to the distance between contours.
Industry:Earth science
A method of deriving, from distances measured at or computed for the Earth's surface, equivalent distances on the ellipsoid of reference. The distances on the Earth's surface are reduced to the those distances on the geoid which lie on the same normals to the ellipsoid. Angles measured at or computed for the Earth's surface are referred to the geoid without change except for those angles determined at large elevations, when a small correction may be applied. Then, starting from the origin, the distances and angles on the geoid are developed onto the ellipsoid in such a manner that distances and angles remain unchanged throughout the process.
Industry:Earth science
A measure of length, in its origin the length of the forearm from the elbow to the extremity of the middle finger, but of uncertain length in standard units such as inches or centimeters; in English measure, 18 inches (45. 72 cm)
Industry:Earth science
A correction applied to a reading observed with a micrometer equipped microscope, to compensate for the difference between the nominal distance the moving line is moved by one turn of the micrometer screw and the actual distance is moved.
Industry:Earth science
