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Diagram showing displacement of the Sun's image at sunrise and sunset Comparison of inferior and superior mirages due to differing air refractive indices, n. Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. [1]
Levelling refraction refers to the systematic refraction effect distorting the results of line levelling over the Earth's surface. In line levelling, short segments of a line are levelled by taking readings through a level from two staffs, one fore and one behind. By chaining together the height differences of these segments, one can compute ...
The calculated values are approximations due to the distinction between common/geodetic latitude and geocentric latitude. However, the two values differ by less than 12 minutes of arc, which is less than the apparent angular radius of the sun. The formula also neglects the effect of atmospheric refraction. [5]
"Modelling atmospheric delays in the analysis of space geodetic data" (PDF). In De Munck, J. C.; Spoelstra, T. A. Th. (eds.). Proceedings of Refraction of Transatmospheric Signals in Geodesy. Vol. 36. Netherlands Geodetic Commission Publications on Geodesy. pp. 157– 164. (invited lecture)
Klein quartic with 28 geodesics (marked by 7 colors and 4 patterns). In geometry, a geodesic (/ ˌ dʒ iː. ə ˈ d ɛ s ɪ k,-oʊ-,-ˈ d iː s ɪ k,-z ɪ k /) [1] [2] is a curve representing in some sense the locally [a] shortest [b] path between two points in a surface, or more generally in a Riemannian manifold.
In general relativity, a geodesic generalizes the notion of a "straight line" to curved spacetime.Importantly, the world line of a particle free from all external, non-gravitational forces is a particular type of geodesic.
A wooden tripod holding an optical level is set up firmly on the ground. Levelling or leveling (American English; see spelling differences) is a branch of surveying, the object of which is to establish or verify or measure the height of specified points relative to a datum.
Seismic methods, such as reflection seismology, seismic refraction, and seismic tomography. This type of survey is carried out to discover the detailed structure of the rock formations beneath the surface of the Earth. Seismoelectrical method; Geodesy and gravity techniques, including gravimetry and gravity gradiometry. This type of survey is ...