- Branche: 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 method of determining the location of a station from observations made on a satellite, and depending on a knowledge of the satellite's orbit for determining the satellite's location at the instant of observation.
Industry:Earth science
Copy number 27, given to the USA in 1899, of the International Prototype Meter.
Industry:Earth science
A navigation system determining the distance of a mobile unit from two or more fixed stations, by measuring the time needed for a signal to travel between the mobile unit and each of the fixed stations. One measured distance locates the mobile unit on a circle with its center at a known station and a known radius equal; a second measured distance locates the mobile unit on a second circle with known center and radius. If the unit has not moved between the two measurements, it is located at one of the two intersections of the two circles. If it has moved, an estimated velocity and location are used to correct for the lapse in time.
Industry:Earth science
A modification of Loran-C in which the baseline is considerably shortened.
Industry:Earth science
A hyperbolic navigation system of the Loran type operating at 100 kHz. The system is similar to Loran A but has greater range and higher accuracy. It matches the phase of the signals instead of their envelopes, uses a different coding of the signals, incorporates a cesium clock to give more accurate control of the timing, and puts more power into the signals, which are in Golay code. Locations can be determined at distances up to 1 500 km over land and 3 000 km over water, but less accuracy is obtainable at greater distances. At a distance of 600 km from the master station, a good intersection will have an accuracy of about 150 meters. At 2 000 km, over water, an accuracy of about 500 meters may be obtained. However, an error of one cycle in determining phase would produce an error of about 8 km. Predictable accuracy is better than 400 meters within the region covered, and the precision is better than 18 90 meters.
Industry:Earth science
The length of 1 minute of longitude on the Equator, on a spheroid representing the Earth.
Industry:Earth science
A map prepared for studying and planning the control of floods in regions subject to floods.
Industry:Earth science
A map based at least in part on data from an original survey but based on a number of fixed points insufficient to maintain accuracy of scale and location consistently. This is not the same as a sketch map.
Industry:Earth science
One of two map projections devised by Nell: a modification of the globular map projection, and an equal area map projection combining the Bonne map projection and Lambert's conical equal-area map projection.
Industry:Earth science
The line in which the plane of the celestial meridian intersects the plane of the horizon. The astronomical azimuth of a meridian line is 0<sup>o</sup> or 180<sup>o</sup>.
Industry:Earth science
