Bulletin Géodésique (1946-1975)

, Volume 85, Issue 1, pp 237–247 | Cite as

Changes of spheroid and of datum

  • J. A. Weightman
Second International Symposium on Geodetic Calculations (Bruxelles, June 1966)
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Summary

A datum change between two geodetic systems with points in common may be derived in three stages; slight adjustments of coordinates to make the networks of common points geometrically similar in the two systems; a scale factor to make them geometrically congruent; finally, an orthogonal transformation to swing them into coincidence.

The geometrical concept is developed of a “datum screw”, not arbitrarily chosen as is the “origin” or “datum point” of a geodetic survey, but intrinsic to the geometry. The conditions under which it degenerates to a simple “datum shift” are discussed.

Differential and other formulae for changes of spheroid and of datum are given, together with a set of tables of coefficients.

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Copyright information

© Bureau Central de L’Association Internationale de Géodésie 1967

Authors and Affiliations

  • J. A. Weightman
    • 1
  1. 1.Geodetic OfficeFelthamEngland

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