Thaddeus Vincenty (born Tadeusz Szpila; 27 October 1920 – 6 March 2002) was a Polish American geodesist who worked with the U.S. Air Force and later the National Geodetic Survey to adapt three-dimensional adjustment techniques to NAD 83.He devised Vincenty's formulae, a geodesic calculation technique published in 1975 which is accurate to about half a millimeter. His contributions to the NAD 83 include the introduction of three dimensional Earth-centered coordinates, which unifies locations on Earth with locations in space, an essential development for the Global Positioning System.