ED50 ("European Datum 1950", EPSG:4230
) is a
geodetic datum
A geodetic datum or geodetic system (also: geodetic reference datum, geodetic reference system, or geodetic reference frame) is a global datum reference or reference frame for precisely representing the position of locations on Earth or other plan ...
which was defined after
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
for the international connection of
geodetic network
A geodetic control network (also geodetic network, reference network, control point network, or control network) is a network, often of triangles, which are measured precisely by techniques of terrestrial surveying or by satellite geodesy.
A ...
s.
Background
![Kriegsweihnacht 1940-Hemmerich](https://upload.wikimedia.org/wikipedia/commons/5/50/Kriegsweihnacht_1940-Hemmerich.jpg)
Some of the important battles of
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
were fought on the borders of
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
, the
Netherlands
)
, anthem = ( en, "William of Nassau")
, image_map =
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of the Netherlands
, established_title = Before independence
, established_date = Spanish Netherl ...
,
Belgium
Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...
and
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, and the mapping of these countries had incompatible
latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
and
longitude
Longitude (, ) is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter l ...
positioning. During the war the German Military Survey (Reichsamt Kriegskarten und Vermessungswesen), under the command of Lieutenant General Gerlach Hemmerich, began a systematic mapping of the areas under the control of the German Military, a large part of Europe.
The allies were also concerned about the state of mapping in Europe, and in 1944 the
US Army Map Service set up an intelligence team to collect mapping and surveying information from the Germans as the allied armies moved through Europe after the
Normandy landings
The Normandy landings were the landing operations and associated airborne operations on Tuesday, 6 June 1944 of the Allied invasion of Normandy in Operation Overlord during World War II. Codenamed Operation Neptune and often referred to as ...
. The group, known as Houghteam after Major Floyd W. Hough, collected much material. Their greatest success was in April 1945. They found a large cache of material in
Saalfeld
Saalfeld (german: Saalfeld/Saale) is a town in Germany, capital of the Saalfeld-Rudolstadt district of Thuringia. It is best known internationally as the ancestral seat of the House of Saxe-Coburg and Gotha, Saxe-Coburg and Gotha branch of the S ...
,
Thuringia
Thuringia (; german: Thüringen ), officially the Free State of Thuringia ( ), is a state of central Germany, covering , the sixth smallest of the sixteen German states. It has a population of about 2.1 million.
Erfurt is the capital and larg ...
, which proved to be the entire geodetic archives of the German Army. The shipment, 75 truckloads in all, was transferred to
Bamberg
Bamberg (, , ; East Franconian: ''Bambärch'') is a town in Upper Franconia, Germany, on the river Regnitz close to its confluence with the river Main. The town dates back to the 9th century, when its name was derived from the nearby ' castle. C ...
, and then to Washington for evaluation.
Shortly after this, the team captured the personnel of the Reichsamt für Landesaufnahme, the State Surveying Service, in
Friedrichroda
Friedrichroda () is a town in the district of Gotha, Thuringia, Germany. It is situated at the north foot of the Thuringian Forest, 21 km by rail southwest of the town of Gotha. It is surrounded by fir-clad hills and possesses numerous han ...
, also in Thuringia. This group had been working on the integration of the mapping of the occupied territories with that of Germany, under Professor Erwin Gigas, a
geodesist
Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivale ...
with an international reputation. They were directed to continue this work, in Bamberg in the US zone of occupation, as part of the US-led effort to develop a single adjusted
triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points.
Applications
In surveying
Specifically in surveying, triangulation involves only angle me ...
for
Central Europe
Central Europe is an area of Europe between Western Europe and Eastern Europe, based on a common historical, social and cultural identity. The Thirty Years' War (1618–1648) between Catholicism and Protestantism significantly shaped the area' ...
. This was completed in 1947.
The work was then extended to cover much of
Western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context.
The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean ...
which was completed in 1950, and became ED50.
[
The European triangulation was originally classified military information. It was de-classifired in the 1960s, and became the basis for the definition of international boundaries in the North Sea.] It was, and still is, used in much of Western Europe apart from Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...
, Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...
, Sweden
Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...
and Switzerland
). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...
, which have their own datums.
It used the International Ellipsoid
The Hayford ellipsoid is a geodetic reference ellipsoid, named after the US geodesist John Fillmore Hayford (1868–1925), which was introduced in 1910. The Hayford ellipsoid was also referred to as the International ellipsoid 1924 after it had be ...
of 1924 (" Hayford-Ellipsoid" of 1909) (radius
In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...
of the Earth's equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
6378.388 km, flattening
Flattening is a measure of the compression of a circle or sphere along a diameter to form an ellipse or an ellipsoid of revolution (spheroid) respectively. Other terms used are ellipticity, or oblateness. The usual notation for flattening is ...
1/297, both exact). That spheroid was an early attempt to model the whole Earth and was widely used around the world until the 1980s when GRS 80
The Geodetic Reference System 1980 (GRS 80) is a geodetic reference system consisting of a global reference ellipsoid and a normal gravity model.
Background
Geodesy is the scientific discipline that deals with the measurement and representation ...
and WGS 84
The World Geodetic System (WGS) is a standard used in cartography, geodesy, and satellite navigation including GPS. The current version, WGS 84, defines an Earth-centered, Earth-fixed coordinate system and a geodetic datum, and also descri ...
were established.
Many national coordinate systems of Gauss–Krüger are defined by ED50 and oriented by means of geodetic astronomy
Geodetic astronomy or astronomical geodesy (astro-geodesy) is the application of astronomical methods into geodetic networks and other technical projects of geodesy.
Applications
The most important applications are:
* Establishment of geodetic da ...
. Up to now it has been used in database
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases sp ...
s of gravity fields, cadastre
A cadastre or cadaster is a comprehensive recording of the real estate or real property's metes and bounds, metes-and-bounds of a country.Jo Henssen, ''Basic Principles of the Main Cadastral Systems in the World,'/ref>
Often it is represented gra ...
, small surveying
Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ca ...
networks in Europe and America, and by some developing countries with no modern baselines. ED50 was also part of the fundamentals of the NATO
The North Atlantic Treaty Organization (NATO, ; french: Organisation du traité de l'Atlantique nord, ), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two No ...
coordinates ( Gauss–Krüger and UTM) up to the 1980s.
The geodetic datum of ED50 was centred at the Helmertturm on the Telegrafenberg
The Einstein Tower (German: ''Einsteinturm'') is an astrophysical observatory in the Albert Einstein Science Park in Potsdam, Germany built by architect Erich Mendelsohn. It was built on the summit of the Potsdam '' Telegraphenberg'' to house ...
in Potsdam
Potsdam () is the capital and, with around 183,000 inhabitants, largest city of the German state of Brandenburg. It is part of the Berlin/Brandenburg Metropolitan Region. Potsdam sits on the River Havel, a tributary of the Elbe, downstream of B ...
, (then East) Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
; the intent was to encourage cooperation with the socialist states during the cold war
The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
, which failed. The adjustments for later versions of the datum ( ED77, ED79) used the Munich Frauenkirche
, native_name =
, native_name_lang =
, image = Frauenkirche Munich - View from Peterskirche Tower2.jpg
, pushpin map =
, pushpin label position =
, pushpin map alt =
, pushpin mapsize ...
as starting point.
Datum shift between ED50 and WGS 84
The longitude and latitude lines on the two datums are the same in the Archangel
Archangels () are the second lowest rank of angel in the hierarchy of angels. The word ''archangel'' itself is usually associated with the Abrahamic religions, but beings that are very similar to archangels are found in a number of other relig ...
region of north-west Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
. As one moves westwards across Europe, the longitude lines on ED50 gradually become further west than their WGS 84 equivalents, and are around 100 metres west in Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, i ...
and Portugal
Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...
. Moving southwards, the latitude lines on ED50 gradually become further south than the WGS 84 lines, and are around 100 m south in the Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...
.
This means that 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 is due to the fact that the International Ellipsoid is larger than the GRS 80/WGS 84 ellipsoid, 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
The Universal Transverse Mercator (UTM) is a map projection system for assigning coordinates to locations on the surface of the Earth. Like the traditional method of latitude and longitude, it is a horizontal position representation, which means i ...
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 WGS 84 UTM northing lines. UTM northings are measured from the Equator; distance from the equator to latitude 50 degrees is 112 m more on the International than on the WGS 84 spheroid.
References
{{reflist
See also
* The French datum RGF93
* The Great Britain datum OSGB36
The Ordnance Survey National Grid reference system (OSGB) (also known as British National Grid (BNG)) is a system of geographic grid references used in Great Britain, distinct from latitude and longitude.
The Ordnance Survey (OS) devised the ...
.
* For Ireland, the Irish Transverse Mercator
Irish Transverse Mercator (ITM) is the geographic coordinate system for Ireland. It was implemented jointly by the Ordnance Survey Ireland (OSi) and the Ordnance Survey of Northern Ireland
{{Unreferenced, date=April 2021
Ordnance Survey of N ...
.
* The Swedish datum RT90 The Swedish grid (in Swedish Rikets Nät, RT 90) is a coordinate system that was previously used for government maps in Sweden. RT 90 is a slightly modified version of the RT 38 from 1938. RT 90 has been replaced with SWEREF 99 as the official Swe ...
.
* The Switzerland datum CH1903 The Swiss coordinate system (or Swiss grid) is a geographic coordinate system used in Switzerland and Liechtenstein for maps and surveying by the Swiss Federal Office of Topography (Swisstopo).
A first coordinate system was introduced in 1903 under ...
.
Geodesy
Geographic coordinate systems