site search by freefind

follow me


Geodetic Datum Geodetic Reference System
A geodetic datum (plural is datums) definition has a change of semantics and meaning.
  • at the beginning, a geodetic datum was the astronomic and geodetic determination of size, position (fundamental point) and orientation (Laplace azimuth) of a local, regional or national reference system. Mainly, they had no relationship to other reference systems
    • in geomatics a geodetic datum often means the datum transformation parameters from a national to a global geodetic reference system.
  • modern geodetic reference systems are determinded in a combination of many geodetic and astronomic measurements like Global Satelite Navigation System (GNSS), Very Long Baseline Interferometry (VBLI) etc. They are positionned earth centered.