- 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, ...
A magnetometer determining the intensity of a magnetic field by measuring the frequency (Larmor precession frequency) with which atomic electrons in the field precess. The electrons in an atom move in orbits about the nucleus. As moving charges, they experience a force, in a magnetic field, proportional to the intensity of the field and in a direction perpendicular to the plane of the orbit. The orbit therefore precesses about the nucleus at a rate proportional to the intensity of the field. The frequency is measured by passing light of the proper frequency through a gas and measuring the frequency (equal to the Larmor frequency) at which the light is strongly absorbed when modulated by a weak magnetic field applied to the gas.
Industry:Earth science
A section of waterfront and adjacent water at which both local and transient pleasure-boats are accommodated, usually with other facilities for fueling boats, feeding passengers, etc.
Industry:Earth science
The comparison of a map of a region with the appearance of that region as it is being observed by a scanning device aboard a craft above that region. The technique is used for guiding aircraft, rockets, spacecraft, ships and submarines (the two latter type of craft using sonic scanners).
Industry:Earth science
(1) Those characteristics of a piece of land which are used in defining its boundary. Metes and bounds include measurements as well as monuments, etc. A metes and bounds description of a piece of land is a complete description of the boundary, with the distances (metes) and directions given sequentially around the perimeter (bounds) of the piece. (2) The boundary lines or limits of a piece of land.
Industry:Earth science
A durable article deposited in the ground at the location of a corner to perpetuate that location should the monument there be removed or destroyed. The memorial is usually deposited at the base of the monument and may consist of anything durable such as glass or stoneware, a marked stone, charred stake or quantity of charcoal.
Industry:Earth science
Any method used for testing or checking the accuracy of a topographic map. Accuracy can be tested, e.g., by running traverses and level-lines across selected regions of a map sheet and comparing the horizontal coordinates of features determined from the map with the coordinates of the same features determined by traverse, and the elevations of features as given on the map with the elevations of those features as determined by leveling.
Industry:Earth science
A thermometer which automatically registers the highest temperature to which it has been exposed since its last setting.
Industry:Earth science
Comparing a star chart with the appearance of the sky as it is being observed by a scanning device aboard an vehicle on the surface, in the air, or in outer space. The technique is used for guiding aircraft, rockets, spacecraft, ships and sometimes, land-based vehicles.
Industry:Earth science
(1) Dead reckoning by double integration of the output of accelerometers whose orientations are fixed in inertial space, i.e., fixed with respect to the distant galaxies. (2) The process of measuring a craft's velocity, orientation (in some applications), and displacement from a known starting point by measuring the accelerations acting on the craft in known directions, by means of devices such as accelerometers and gyroscopes.
Industry:Earth science
