"Geodesy (/dʒiːˈɒdɪsi/) is the Earth science of accurately measuring and understanding Earth´s geometric shape, orientation in space and gravitational field. The field also incorporates studies of how these properties change over time and equivalent measurements for other planets (known as planetary geodesy). Geodynamical phenomena include crustal motion, tides and polar motion, which can be studied by designing global and national control networks, applying space and terrestrial techniques and relying on datums and coordinate systems." - (en.wikipedia.org 06.01.2021)
en