- Branche: Earth science
- Number of terms: 93452
- Number of blossaries: 0
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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, ...
One of the two coordinates of a point, on a stereoscopic pair of images, as determined by measuring with a stereoscopic plotting instrument.
Industry:Earth science
A variant of the oblique Mercator map-projection used for maps made from pictures taken by LANDSAT satellites. The central line follows the undulating ground-track (foot-point) of the satellite rather than an ellipse or great circle. The initial concept was due to A. Colvocoresses.
Industry:Earth science
The nearly constant amount by which a particular observer's timing of the transit of faint stars is later than his timing of the passage of bright stars.
Industry:Earth science
The method used in making measurements of a specific kind, as defined collectively by specifying the apparatus and auxiliary equipment used, the operations performed and their sequence and the conditions under which they are performed.
Industry:Earth science
(1) As defined by the courts, the highest price estimated in terms of money which a property would bring if exposed for sale in the open market, allowing a reasonable time to find a purchaser who buys with a knowledge of all the uses to which the property is adapted and for which it is capable of being used. (2) The price at which a willing seller would sell and a willing buyer would buy, neither being under abnormal pressure. (3) The price expectable if a reasonable time is allowed to find a purchaser and if both seller and buyer are fully informed. The essential difference between market price and market value lies in the premises of intelligence, knowledge, and willingness, all of which are contemplated in setting the market value but not in the market price. Stated differently, at any given moment of time the value connotes what a property is actually worth and market price what it may be sold for. Note, however, that the concept of actually worth is itself defined by the definition of market value and has no meaning apart from it.
Industry:Earth science
A level consisting of a pool of mercury in a container attachable to a transit in such a manner that the surface of the mercury is visible and can be used for indicating a level surface. In one form, called a mercury leveler, the surface is viewed through a telescope (autocollimator) attached to the instrument to be leveled. When the cross-hairs of this telescope appear to coincide with the reflection of the cross-hairs from the surface of the mercury, the line or sight is level.
Industry:Earth science
That portion of the lithosphere extending downward from the bottom of the crust (the Mohorovicic discontinuity) to about 2 900 km. At the upper surface of the mantle, the speed of longitudinal seismic waves jumps from about 7 km/s to over 8 km/s; at the lower boundary, only longitud-inal seismic waves can travel on down into the core. Close to the upper boundary of the mantle, about 100 - 200 km below the Earth's surface, is a zone in which seismic waves travel at speeds lower than those occurring at greater depths. This zone in the upper mantle has been called the asthenosphere, rheosphere and upper mantle. However, the term asthenosphere has also been applied to the mantle as a whole.
Industry:Earth science
The line, or the length of the line, at the scale of the stereoscopic model, joining the perspective centers as reproduced by the stereoscopic instrument.
Industry:Earth science
A corner established at (a) the intersection of a surveyed subdivision-of-section line and a meander line; or (b) the intersection of a computed center line or a section and a meander line. In the latter case, the center line of the section is calculated and surveyed on a theoretical bearing to an intersection with the meander line of a lake (over 50 acres in area) which is located entirely within a section.
Industry:Earth science
A feature of relief, drainage, and other landforms, identifiable on photographs but too small to appear on maps.
Industry:Earth science
