- 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, ...
The angle by which a ray passing from a point P through the projection center is deviated from a straight line.
Industry:Earth science
The formula tan A = Sin H sec <font face = symbol>f</font> cot <font face = symbol>d</font> (1/(1 a)) where a = tan <font face = symbol>f</font> cot <font face = symbol>d</font> cot H, for the astronomical azimuth A of a celestial body in terms of the body's astronomical latitude <font face = symbol>f</font>, declination <font face = symbol>d</font> and hour angle H. The function 1/(1 a) has been tabulated.
Industry:Earth science
The method used in determining the stated accuracy of a product.
Industry:Earth science
The apparent arc described above (diurnal arc) or below (nocturnal arc) the horizon by the Sun or other celestial body.
Industry:Earth science
The assumption that radial directions are correct if measured at the principal point. The assumption is satisfactory only for nearly vertical photographs.
Industry:Earth science
(1) The angle, in a horizontal plane, from a vertical plane through the horizontal axis of a meridian telescope to the prime vertical through the center of that axis. Alternatively, the angle by which the east west axis of the telescope deviates from being perpendicular to the plane of the meridian. It is considered positive if the nominally west end of the horizontal axis points south of west. (2) The angle defined similarly (to 1) for any telescope with an alt azimuth mounting when the horizontal axis should be perpendicular to the meridian. (3) For any instrument for which a nearly vertical plane can be defined, the difference between the azimuth of that plane and the azimuth in which it is supposed to lie. This definition is often applied to the calibration of radio telescopes.
Industry:Earth science
A system for determining heights of terrain along a line of flight by using an airborne laser altimeter for measuring height variations in the terrain and a combination of accelerometers, gyroscopes, optical distance measuring instrument (DMI) and computer for determining the position of the altimeter. Corner cube reflectors are placed on geodetic markers. The DMI measures distance and direction (with respect to the gyroscopic system) to these reflectors; this information, together with information from accelerometers and gyroscopes, is sent to the computer which determines position from these data. The system was developed for the U. S. Geological Survey by C. S. Draper Laboratories.
Industry:Earth science
A range of wavelengths or frequencies in the electromagnetic spectrum within which radiant energy is absorbed by a substance.
Industry:Earth science
Aerotriangulation adjustment carried out by first adjusting the coordinates of points imaged in a strip of photographs so that the relative orientations are correct, then transferring the coordinate system of the strip to ground control. A form of strip aerotriangulation adjustment.
Industry:Earth science
All of the air space lying within the boundaries of the approach zone district at an airport and lying above the floor of the district.
Industry:Earth science
