Geodetic surveying

Since 1893, the U.S. basis of length measurement has been derived from metric standards. In 1959, a small refinement was made in the definition of the yard to resolve discrepancies both in this country and abroad which changed its length from 3600/3937 m to 0.9144 m exactly. This resulted in the new value being shorter by two parts in a million. At the same time, it was decided that any data in feet derived from and published as a result of geodetic surveys within the U.S. would remain with the old standard (1 ft = 1200/3937 m) until further decision. This foot is named the U.S. survey foot. As a result, all U.S. land measurements in U.S. customary units will relate to the meter by the old standard. All the conversion factors in this table for units referenced to this footnote are based on the U.S. survey foot rather than on the international foot. 

Cotidal line A line on a chart or map passing through places having the same tidal hour.(The explanations in the footnotes partly were taken from Tide and Current Glossary, Special Publication No. 228, Coast and Geodetic Survey, by Paul Schureman, 1941.)... 

Schureman, P, 1941. Manual of harmonic analysis and prediction of tides. U. S. Coast and Geodetic Survey, Special Puhi. No. 98, 317 p. 

U.S. Coast and Geodetic Survey—water transportation statistics... 

Absolute elevation planes at the plant site are referred to sea level via bench marks erected by the U.S. Geodetic Survey or state surveys. Within the plant area, a reference datum level, generally at the lowest point on the site, is more useful in specifying plant elevations. 

Chamber of Commerce, 283 Coastal and Geodetic Survey, 269 Departments, Agriculture, 38 Commerce, 269 Defense, 31 Interior, 269... 

Texas Tower TT-4 Platform off the eastern seaboard. (Courtesy of NOAA s Historic Coast and Geodetic Survey Collection.)... 

U.S. Department of Commerce Report 1966. The Prince William Sound, Alaska Earthquake of /964 and Aftershocks, Vol. 1, Publication 10-3, Coast and Geodetic Survey, Washington, DC, pp. 230-238. 

The examples which are detailed in this section are compiled from published material on the practical applications of GPS to date, and from commercial projects executed by Uniscott Surveys Limited. The latter is a Geodetic Surveying Company, based in Nottingham and specializing in GPS surveys. Examples are also given of applications which are still the subject of current research at Nottingham University and elsewhere. 

Fig.4 shown the preliminary data of measurements at three orders of accuracy (I, II, III). They include the results obtained in 3 periods of geodetic survey (09.1989, 05.1990, 09.1990) and those obtained with a feeler gauge (3-D) employed in the observations conducted at frequency of 1 observation per month. 

The new motorway tunnel under the Ems was created between 1985 and 1989 by the Immersed Tube Method. An account is given below of finished construction, basic geodetic surveys, measurement during construction and examining survey after completion. For the project five tunnel elements prefabricated in a dredged dock, each 127,5m long, had to be set across the Ems and lowered one after the other into position. This necessitated continual, accurate supervision of position, height, and inclination of each tunnel element. 

The measurement values obtained from a geodetic survey have errors. Therefore, if it is possible to estimate the approximate value for the measurement value, then it will be possible to adopt the approximate value instead of the measurement value in the theory of simultaneous adjustment. The approximate values for the eight unknowns tio,vo,c,ai, - in Eq. (6) can be estimated by the equipment such as a camera, video monitor or A/D converter. Therefore, we assume the correction value for each of the unknowns, the difference between the most probable value and the approximate value, to be the measurement value. The least squares equation for the calibration in the 2-D field can be written as follows ... 

Chikatsu H., Kasugaya N., Mural S. (1987) An Adjustment of Photogrammetry Combined with the Observation Equations Obtained from the Geodetic Survey. Journal Japan Soc. Photogramm. Remote Sensing, pp 4-20. 

Anonymous (1916). Centennial celebration of the United States Coast and Geodetic Survey. US Dept, of Commerce Washington DC. 

Near-surface disposal units must be marked in such a way that the boimdaries of the units can be easily defined. Three permanent survey marker control points, referenced to USGS or National Geodetic Survey control stations, must be established on the site to facilitate surveys. 

Horizontal and vertical controls must be provided by USGS or National Geodetic Survey control stations as checked against USGS or National Geodetic Survey record files. 

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