- 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, ...
Navigation of a vehicle or craft by star-chart matching (q.v.).
Industry:Earth science
The interval of time between two successive passes of the Moon through the same equinox. The tropical month can be measured by the length of time it takes the Moon to revolve from a given celestial longitude back to the same longitude, reckoned from an equinox affected by precession. The tropical month contains, on the average, 27.321528 mean solar days. Because of perturbations of the Moon's orbit, the actual length varies by about 7 hours. The difference between the lengths of the sidereal and tropical months is caused by the precession of the equinoxes.
Industry:Earth science
An oblique meridian chosen as the referent from which longitudes and time are calculated.
Industry:Earth science
(1) A line, in a body of water, every point of which is equidistant from the nearest points on opposite banks or other points of reference. (2) The line lying at the same distance from two non-parallel lines. (3) A line every point of which is equidistant from the two nearest points on the baselines from which the breadth of the territorial sea of each of two coastal nations is measured. The term was adopted at the Geneva Conference on the Law of the Sea in 1958.
Industry:Earth science
A map projection which represents the pole as the arc of a circle of finite length.
Industry:Earth science
A negative having open parts (i.e., having small parts cut out) and used as a mask where screens, rulings or tints are to be printed in the uncovered parts.
Industry:Earth science
An equal-area map projection, invented by J.E.E. Craster (1929), representing parallels of latitude by straight lines parallel to the line representing the equator and the meridians by parabolas with vertices at the line representing the equator.
Industry:Earth science
(1) The central number, in a set of numbers arranged in order of size, if the set contains an odd number of numbers; it is the average of the two central numbers if the set contains an even number of numbers. (2) A longitudinal strip of road separating opposing streams of traffic. A median may be raised above the level of the road or be flush with it; it may consist of reinforced rails or concrete barriers.
Industry:Earth science
A map printed using fluorescent inks or on fluorescent paper. The map can be read in darkness under ultraviolet radiation.
Industry:Earth science
