- 行业: 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 rate of change of a clock correction; the amount gained or lost by a clock in a unit of time. When applied to a chronometer, the quantity is called chronometer rate. Clock rate is usually expressed as the increase or decrease of the clock correction per day, hour, or minute as shown on the clock's face. If the clock correction is decreasing algebraically, the clock is gaining and the rate is negative; if the correction is increasing, the clock is losing and the rate is positive.
Industry:Earth science
A chart designed for use in navigating ships, boats, or other watercraft.
Industry:Earth science
A board established by the act of 25 July 1947, (61 Stat 456, 43 U. S. C. 365) to provide uniformity in geographic nomenclature and orthography through-out the Federal Government. Membership is comprised of a group appointed by various governmental departments and agencies. Subject to approval by the Secretary of the Interior, the Board formulates principles, policies, and procedures on domestic and foreign geographic names and their spelling.
Industry:Earth science
A mirror or arrangement of mirrors rotated at such a rate by a motor as to direct light from the stars into a fixed direction on the ground, e.g., into a stationary telescope.
Industry:Earth science
A point, on a photograph, which is used as a radial center (because of its ready identifiability) instead of the principal point, the nadir point, or the isocenter.
Industry:Earth science
Periodically interrupting, by means of a shutter, that photographic image of the track of a star or artificial satellite which is produced when the camera's position is held fixed. Chopping is used to provide points on the photograph whose coordinates and be measured precisely and whose times of creation are known.
Industry:Earth science
A structure, including its supports, erected over a depression or an obstruction, having a track or passageway for carrying traffic or other moving loads, an having an opening measured along the center of the roadway of more than 20 feet between undercopings of abutments or spring-lines of arches, or extreme ends of openings for multiple boxes. It may include several pipes, where the clear distance between openings is less than half of the smaller contiguous openings.
Industry:Earth science
A circle which moves along a specified curve so as to be tangent to that curve at each point. In particular, in route surveying, the osculating circle to a spiral.
Industry:Earth science
A method of determining corrections α and Δδ to right ascension α and declination α of one star catalog with respect to the right ascension and declination in another by representing the corrections as series of associated Legendre functions, e.g.: Δα = Σ Pnm(δ)(Cnm cos mα + Snm sin mα).
Industry:Earth science
That circle, on a rotational ellipsoid, in which a plane through the center of the ellipsoid and perpendicular to the axis of rotation intersects the surface. If the rotational ellipsoid is a sphere, a particular diameter of the sphere is specified as the axis of rotation, or a specific great circle is designated as the equatorial circle.
Industry:Earth science
