The European date 1950 ( ED50 ) is a geodetic datum, in which the international measurement network of the Western European states was calculated from 1950. This European network is a precise association of approximately 20 public triangulation in order to expand on the basics of Earth Sciences in time of increasing international cooperation they can. It also played a role for some developing countries and global analyzes. In North America, the North American Datum him ( NAD) corresponds.
It is based on the International Ellipsoid of 1924 ( often referred to only by author John Fillmore Hayford ) and has as its fundamental point of the Helmertturm on the Telegrafenberg in Potsdam. The ellipsoid is therefore relative to the earth body supported so that it touches the geoid in Potsdam. For the choice of this survey point to its relatively central location spoke ( for Western Europe, Scandinavia and Southern Europe). The occupying army of the United States supported this initiative ( by additional qualified personnel, computer, etc.) and saw it as an opportunity to move parts of the Eastern Bloc for Cooperation (which hardly took place). The choice of the Hayford ellipsoid instead of the Bessel ellipsoid - which would be the geoid in Europe better adapted - is related to the dominance of the U.S. after the second world war together, and with some plans, the 50 later to use ED to other continents.
Two decades later, the ED 50 was extended to the ED 77 and ED 79 for. On the same basis - but with recent measurements and taking into account the reduction due to deflection of the vertical, the measurement network of the ED 79 since the most important data material for comparison with measurements of satellite geodesy. The ED 50 is still used for various cards, as programmed in GPS receivers data base and coordinate transformation, however, has made for new projects his successors or the WGS 84 space.
Currently, the following data are used: