Higher geodesy

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The higher geodesy is the part of Geodesy that deals with the large-scale shape of the earth ( earth's shape , geoid ), their movements (especially earth's rotation , nutation , continental drift ) and the Earth's gravity is concerned.

The term was coined by Friedrich Robert Helmert (1843-1917). From 1866 onwards, Josef Philipp Herr was professor for spherical astronomy and higher geodesy at the kk Polytechnic Institute in Vienna, head of the first special lecturer's chair for earth measurements in Europe.

The associated measurements are carried out terrestrially , with artificial earth satellites and quasars . Their evaluation is based on geometric and physical theories and requires the definition, application and transformation of global and local coordinate systems .

The term higher geodesy originated in contrast to lower geodesy (today applied geodesy , practical geodesy or piece measurement , English: surveying ). In lower geodesy one can neglect the curvature of the earth . In the higher geodesy and the national survey , however, it must always be taken into account. It is almost 1 mm in height at 100 m, and 8 cm at 1 km. The influences on the position measurement only become noticeable at somewhat greater distances.

The higher geodesy is divided into several areas, which, however, partially overlap. The following classification is common:

The mentioned fields of work also concern parts of geophysics and geodynamics as well as navigation , potential theory and differential geometry .

Recently, the field of higher geodesy has also expanded to near-Earth space - especially to the moon ( selenodesy ) and Mars ( “areodesy” ), but also to other planets (“planetary geodesy”), see also planetology .

See also

Individual evidence

  1. Herr, Josef Philipp. In: Austrian Biographical Lexicon 1815–1950 (ÖBL). Volume 2, Verlag der Österreichischen Akademie der Wissenschaften, Vienna 1959, p. 290.