ED50

ED50

ED 50 (European Dat 1950) is a geodetic datum which was defined after World War II for the international connection of geodetic networks.

Some of the important battles of World War II were fought on the borders of Germany, the Netherlands, Belgium and France, and the mapping of these countries had incompatible latitude and longitude positioning. This led to the setting up of ED50 as a consistent mapping datum for much of Western Europe. It was, and still is, used in much of Western Europe apart from Great Britain, Ireland, Sweden and Switzerland, which have their own datums.

It used the International Ellipsoid of 1924 ("Hayford-Ellipsoid" of 1909) (radius of the Earth's equator 6378.388 km, flattening 1:297). (That spheroid was an early attempt to model the whole Earth and was widely used all over the world up to the 1980s, when GRS80 and WGS84 were established.)

Many national coordinate systems of Gauss–Krüger are defined by ED50 and oriented by means of geodetic astronomy. Up to now it has been used in data bases of gravity field, cadastre, small surveying networks in Europe and America, and by some developing countries with no modern baselines.

The geodetic datum of ED50 is centred at the Munich Frauenkirche in southern Germany, where the approximate centre of the Western Europe national networks was situated in the years of the cold war. ED50 was also part of the fundamentals of the NATO coordinates (Gauss–Krüger and UTM) up to the 1980s.