- 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 pair of filar pendulums differing in length by 1 toise, as used in Bessel's pendulum apparatus of 1826 1827, and having a special kind of suspension.
Industry:Earth science
A graph of the volume of a reservoir, tank, etc. , as a function of the height of the water referred to some horizontal surface.
Industry:Earth science
Determination of the following quantities: (a) calibrated focal length; (b) location of the principal point with respect to the fiducial marks; (c) location of the point of symmetry; (d) the distortion effective in the focal plane of the camera and referred to the particular focal length; and, sometimes, (e) the resolution of the lens system, (f) the degree of flatness at the focal plane, and (g) the opening and closing cycle of the shutter as a function of time. Sometimes the locations of fiducial marks and intersections in a reseau are included in a calibration. If the camera has more than one lens system, calibration includes determining the angles between the optical axes of the individual lens systems. Setting the fiducial marks and positioning the lens system are ordinarily considered adjust-ments, although these actions are sometimes done during calibration. Unless calibration is stated specifically to be of a camera, distortion and other optical characteristics of a lens system are determined in a focal plane located at the equivalent focal length and the process is called lens calibration.
Industry:Earth science
(1) A sheet of glass, plastic, or metal made to show, according to the data provided by calibration of a camera, the relationship of the principal point to the fiducial marks. A calibration templet is used to rapidly and accurately mark principal points on a sequence of photo-graphs. (2) A sheet of glass, plastic, or metal made to show, according to the data obtained by calibration of a multiple lens camera, the relationships of the principal points to the fiducial markers and used to assemble the photographs from the individual photographs into one composite photograph.
Industry:Earth science
A satellite acting as a relay for electromagnetic radiation carrying signals between stations on the ground. Communications satellites are of two kinds: active communications satellites, which receive, amplify and re-transmit signals, and passive communications satellites, which act merely as reflectors for radiation aimed at them. Both kinds have been used as beacons for geodetic surveying.
Industry:Earth science
One of a set of numbers obtained by calibrating a camera and giving the calibrated focal length and the relationship of the principal point to the fiducial marks.
Industry:Earth science
(1) That point, in an actual pendulum or other swinging body, which lies on the line joining the point of suspension and the center of mass, and which is at a distance l<sub>o</sub> from the point of suspension; l<sub>o</sub> is the length of a simple, hypothetical pendulum having the same frequency of oscillation as the actual pendulum (or other body). If l is the distance from the point of suspension to the center of mass and k is the radius of gyration of the actual pendulum or body, then l<sub>o</sub> = (l² + k²)/l. (2) The point, in a compound pendulum, occupied by the particle which corresponds to the point mass of an equivalent simple pendulum. The center of oscillation and of suspension are interchangeable. If the center of oscillation is made the center of suspension, the former center of suspension becomes the new center or oscillation. This principle is the basis for design of compound reversible pendulums.
Industry:Earth science
The scheme used for classifying a triangulation (process or network) is the same as that used for classifying the control established by that triangulation or contained in that network. (20. 5) The classification adopted by the United States of America recognizes the following categories of geodetic control and, therefore, the same categories of project and network. <br>
Industry:Earth science
