ED50
Encyclopedia
ED 50 is a geodetic datum which was defined after World War II
for the international connection of geodetic network
s.
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 network
s 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.
. 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.)
(This doesn't mean Europe has expanded. The International Ellipsoid is larger than the GRS80/WGS84, so a given north-south distance will cover more latitude on the new ellipsoid, and a given east-west distance will cover more longitude.)
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.
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
for the international connection of geodetic network
Geodetic network
A geodetic network is a network of triangles which are measured exactly by techniques of terrestrial surveying or by satellite geodesy.In "classical geodesy" this is done by triangulation, based on measurements of angles and of some spare distances; the precise orientation to the geographic north...
s.
Some of the important battles of World War II were fought on the borders of Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
and France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, and the mapping of these countries had incompatible latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
and longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
positioning. This led to the setting up of ED50 as a consistent mapping datum for much of Western Europe
Western Europe
Western Europe is a loose term for the collection of countries in the western most region of the European continents, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a geographic entity—the region lying in the...
. It was, and still is, used in much of Western Europe apart from Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
, Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
and Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
, which have their own datums.
It used the International Ellipsoid of 1924 ("Hayford
John Fillmore Hayford
- References :...
-Ellipsoid" of 1909) (radius
Earth radius
Because the Earth is not perfectly spherical, no single value serves as its natural radius. Distances from points on the surface to the center range from 6,353 km to 6,384 km...
of the Earth's equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
6378.388 km, flattening
Flattening
The flattening, ellipticity, or oblateness of an oblate spheroid is a measure of the "squashing" of the spheroid's pole, towards its equator...
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
Geodetic astronomy
Geodetic astronomy is the application of astronomical methods into networks and technical projects of geodesy.The most important topics are:* Establishment of geodetic datum systems Geodetic astronomy is the application of astronomical methods into networks and technical projects of geodesy.The...
. Up to now it has been used in data bases of gravity field, cadastre
Cadastre
A cadastre , using a cadastral survey or cadastral map, is a comprehensive register of the metes-and-bounds real property of a country...
, small surveying
Surveying
See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...
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
Munich Frauenkirche
The Frauenkirche is a church in the Bavarian city of Munich that serves as the cathedral of the Archdiocese of Munich and Freising and seat of its Archbishop. It is a landmark and is considered a symbol of the Bavarian capital city.The church towers are widely visible because of local height...
in southern Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, where the approximate centre of the Western Europe national network
National Network
The National Network is a network of approved state highways and interstates for commercial truck drivers in the United States. The Surface Transportation Assistance Act of 1982 authorized the establishment of a national network of highways designated for use by large trucks. On these highways,...
s was situated in the years of the cold war
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
. ED50 was also part of the fundamentals of the NATO coordinates (Gauss–Krüger and UTM
Universal Transverse Mercator coordinate system
The Universal Transverse Mercator geographic coordinate system uses a 2-dimensional Cartesian coordinate system to give locations on the surface of the Earth. It is a horizontal position representation, i.e...
) 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 RussiaRussia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
. 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
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
and Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
. 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
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
. (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.)
(This doesn't mean Europe has expanded. The International Ellipsoid is larger than the GRS80/WGS84, so a given north-south distance will cover more latitude on the new ellipsoid, and a given east-west distance will cover more longitude.)
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.
See also
- The Great Britain datum OSGB36.
- For Ireland, the Irish Transverse MercatorIrish Transverse MercatorIrish Transverse Mercator , is the geographic coordinate system for Ireland. It was implemented jointly by the Ordnance Survey Ireland and the Ordnance Survey of Northern Ireland in 2001...
. - The Sweden datum RT90.
- The Switzerland datum CH1903.
- The French datum NTF