Everything about Ed50 totally explained
ED 50 (
European Datum 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 was based on the
International Ellipsoid of
1924 ("
Hayford-Ellipsoid" of
1909) (
radius of the Earth's
equator 6378.388 km,
flattening 1:297) and 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.
Datum shift between ED50 and WGS84
The longitude and latitude lines on the two datums are the same in the Archangel region of north-west
Russia. As one moves westwards across Europe, the longitude
lines on ED50 gradually become further west than their WGS84 equivalents, and are around 100 metres west in
Spain and
Portugal. Moving southwards, the latitude
lines on ED50 gradually become further south than the WGS84 lines, and are around 100 m south in the
Mediterranean Sea. (NB. If the
lines are further west, the longitude
value of any given point becomes more easterly. Similarly, if the
lines are south, the
values become northerly.)
The datum shift for the
Universal Transverse Mercator grid is different. The eastings vary between 0 m in Eastern Europe and 100 m in the far west of the continent, roughly similar to the longitude shift, but the northings are about 200 m different across Europe, with the ED50 UTM northing
lines south of the WGS84 UTM northing lines, as UTM northings are measured from the Equator, and the theoretical ED50 Equator is about 200 m south of the WGS84 one.
Further Information
Get more info on 'Ed50'.
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