Geodesy

Geodesy is the science of measuring and representing the geometry, gravity, and spatial orientation of the Earth in temporally varying 3D. It is called planetary geodesy when studying other astronomical bodies, such as planets or circumplanetary systems.^[1]

Geodynamical phenomena, including crustal motion, tides, and polar motion, can be studied by designing global and national control networks, applying space geodesy and terrestrial geodetic techniques, and relying on datums and coordinate systems. The job titles are geodesist and geodetic surveyor.^[2]

^ Vaníček, P.; Krakiwsky, E.J. (1986). Geodesy: the Concepts. New York, US: Elsevier. p. 45. ISBN 0444-87775-4. Until a decade or two ago, geodesy was thought to occupy the space delimited by the following definition (Helmert, 1880, p.3): "Geodesy is the science of measuring and portraying the earth's surface." Then people involved with geodesy began to realize that this definition no longer fully reflected the role contemporary geodesy played and started searching for a new framework. This search probably culminated in the new definition of geodesy, accepted by the National Research Council of Canada (NRC), that we quote here (Associate Committee on Geodesy and Geophysics, 1973): Geodesy is the discipline that deals with the measurement and representation of the earth, including its gravity field, in a three-dimensional time varying space. At the 1975 Grenoble meeting of the Commission on Education of the International Association of Geodesy (see §4.2), a virtually identical definition (Rinner, 1979) was adopted, except for the inclusion of other celestial bodies and their respective gravity fields.
^ "Geodetic Surveyors". Occupational Information Network. 2020-11-26. Retrieved 2022-01-28.