Skip navigation
All Places > Coordinate Reference Systems > Blog > 2016 > February


In Part 1 of this series we saw the setting for the development of a proto European-wide datum by the Germans. This super-National Datum was originally driven from the need of political and military powers in central Europe to comprehensively understand the world around them. Part 2 of the story will concentrate on the Second World War and the Allied military operations that ultimately led to the creation of the European Datum of 1950.


“During the war the German Army also connected triangulations of other European nations to [the German national datum]" Hough 1948


Before 1939 the responsibility with Military Survey at the British War Office was vested in the Geographical Section of the General Staff known as MI4. This Section operated under the Director of Operations and Intelligence, was headed by a Royal Engineer Colonel. Typically the Royal Engineer Colonel would be assisted by Royal Artillery and Infantry Officers. This speaks to the principal application of Military Survey, artillery bombardment and infantry navigation. During the inter-war period a Geodetic sub-section was setup to acquire foreign survey and triangulation data. With increasing evidence in the 1930's that Germany was intending and preparing to launch another war a programme to comprehensively map (and update) the whole of north-eastern France and Belgium (at 1:50,000) began. This effort was led by Colonel P. K. Boulnois under War Office control. To see some of these maps have a look at the plates included in the HMSO book. After the Munich Agreement in 1938 and war with Germany becoming inevitable survey officers were assigned to units for mobilisation. To see more detail concerning MI4 and its organisation see HMSO "Maps and Survey" Books from the War Office e.g. Chapter 01.


War was declared on Germany on the 1st September 1939 after the German invasion of Poland.


By June 1940 the German’s had triumphed in the Battle of France which Adolf Hitler coined "the most famous victory in history”. During the Battle of France the defending British Expeditionary Force was trapped along the northern coast of France, forced to scramble an evacuation of over 338,000 troops to England in the Dunkirk evacuation. After Dunkirk, Germany dominated Western Europe. The British Military reported to Prime Minister Winston Churchill on 4th October that even with the help of other Commonwealth countries and the United States, it would not be possible to regain a foothold in continental Europe in the near future.


Through this interlude where Allied forces fought Axis forces outside of Europe a plan for the invasion of Europe was developed.


Born out of war

The decision to undertake a cross-channel invasion within the next year was taken at the Trident Conference in Washington in May 1943.

Operation Overlord (D-Day)

The Allied operation that launched the successful invasion of German-occupied western Europe during World War II.


The U.S Office of the Chief of Engineers was deployed in WW2 and one of its commitments was to produce, with cooperation of the other allied groups, through revisions and new position readings (see here), battle field situation maps such as the Normandy Landings on 6th June 1944.


Millions of maps were produced throughout the war. The Normandy invasion alone required 3,000 different maps with a total of 70 million copies for keeping the military command fully aware of the operational situation on the ground, in the air and at sea. As the war progressed mapping became more small scale covering larger areas for strategic purposes and it quickly became apparent the lack of geodetic control the allies held over Europe. Probably through national jealously as well as security purposes very little geodetic data was publically available.



Army Group, 12th Engineer Section. August 2, 1944, HQ Twelfth Army Group situation map. Library of Congress Geography and Map Division Washington.


HOUGHTEAM (October 1944 to September 1945)

This lack of geodetic data was particularly noticeable when pushing through France and into Germany making artillery bombardment inaccurate particularly so where shelling took place over the horizon and without seeing the target through gun sights. In this situation of shells going awry the Office of the Chief of Engineers formed a secret intelligence unit in 1944 (Hough, 1947), from the Army Mapping Service (AMS), that was allowed to operate throughout the European Theatre without restrictions. This unit was known as the HOUGHTEAM, named after U.S. Army Major Floyd W. Hough (Chief of the Geodesy Division of AMS) the unit consisted of a team of 3 commissioned officers, 10 enlisted men and 4 engineer consultants.


Their task was to move in behind infantry advancements with the aim of gathering as much cartographic and geodetic information as possible from the enemy, calculating the geodetic transformations into the military mapping system and passing the information onto the army and artillerymen in particular (Hough, 1947).


The HOUGHTEAM moved into Europe in September 1944 and set up in Paris to research and identify targets. The team spent time between in Paris as well as on the front typically arriving on the day it was cleared of enemy personnel. By the spring of 1945 the unit was in Germany and working with the 3rd and 7th armies, providing materials to survey and artillerymen greatly assisting in battle performance. During this time the team captured vital geodetic material for the occupation of Baden-Baden, Württemberg and Bavaria.


“…the war in Europe offered a unique opportunity to exploit known targets and thus to procure from enemy sources captured material of this type both for immediate use of artillery units and for preparation of operational maps.”
Hough 1948

Saalfeld, Thuringia

The most famous raid of this unit was made in spring of 1945, when rumour had it that a cache of geodetic data and instrumentation was held in secret including data on parts of the USSR invaded by Germany. On chance when visiting a hospital for wounded Germany soldiers this rumour was confirmed which led to the discovery on April 17th of a huge cache (Bottoms, 1992) in the village of Saalfeld in Thuringia. Interestingly Saalfeld is close (only ~50Km south west) to the town of Jena in the Jena Valley home of Zeiss Optik, the legendary photogrammetry-equipment company that manufactures just the equipment that HOUGHTEAM were hunting, perhaps the team were exploring this area with this knowledge.


The cache, found in a remote warehouse on the outskirts of Saalfeld turned out to include the entire geodetic archives of the German Army! (Mindling and Bolton, 2008)


In true world war two stories of adventure, the discovery of these documents didn’t finish this story, instead the reader noting the location of Saalfeld and the time of discovery little time was left for grabbing the materials (the advancing Red Army was within days of occupying the town), of which there were 90 tons (Mindling and Bolton, 2008), this equated to around 75 truckloads of geodetic data, maps and instruments that needed transport to Bamburg in the American Occupation Zone.


In realising the difficult logistical task ahead for the HOUGHTEAM the Soviets had already began moving in to their zone of occupation.


According to the story in Life Magazine (12th May 1958)...

“Hough hurriedly borrowed trucks from a U.S artillery unit and the last of them loaded with data was just clearing one side of the village, rushing for the U.S zone, when the Soviets moved in with their tanks on the other side”.

The materials were lifted completely by May 28th destined for Bamberg and onto Washington for evaluation and archiving.


Russian troops arrived in the city the next day.


The horde of information was huge including...

“triangulation surveys running from Moscow to Vladivostok carried out by Germans in the 1900’s planning of the Trans-Siberian Railway […] first order surveys done by the German army deep within the Soviet Union on the Eastern Front” [as well as] the inaccessible regions of the Communist Bloc countries” (Mindling and Bolton, 2008).

The importance of this cache, the realisation that the Soviets were also looking for this cache and its closeness to being compromised by the occupying Soviet forces is suggested by a short quote at a meeting of geodesists in Toronto a few years later where leading Russian delegates mentioned that ...“We have heard a lot about you, Mr. Hough".


The data gathered by the HOUGHTEAM throughout the Second World War, data from Spain into Russia formed the beginning of a framework for European wide geodetic datum and framework for ballistic missile target localisation.


Bottoms, D., 1992. Reference paper 79. World War II Cartographic and Architectural Bank of the National Archives Washington, D.C.Mindling, G., and Bolton, R., 2008. U.S. Air Force Tactical Missiles, 1949-1969, The Pioneers.

Hough, F., (1948) The adjustment of the Central European triangulation network. Bulletin géodésique 7(1) pp64-93

Mindling, G., and Bolton, R., 2008. U.S. Air Force Tactical Missiles, 1949-1969, The Pioneers.

ArcGIS 10.4 now supports eight small-scale map projections displayed in an animated gif:

Compact Miller
Natural Earth
Natural Earth II
Wagner IV
Wagner V
Wagner VII


The Eckert-Greifendorff, Wagner IV and Wagner VII are equal-area projections; the remaining five are compromise projections that try to minimize overall distortion. Sample definitions for the first seven projections are available in the Projected Coordinate Systems\World  and Projected Coordinate Systems\World(Sphere-based) folders.


The Eckert-Greifendorff, Wagner IV and Wagner VII also support ellipsoidal equations. Gnomonic, quartic authalic and Hammer projections are now available in ellipsoidal forms too.


With Eckert-Greifendorff, Hammer ellipsoidal, quartic authalic ellipsoidal, Wagner IV, and Wagner VII, one can select a custom central latitude and create oblique aspects of the projections.


ArcGIS 10.4 includes three variants of polar stereographic projection (variant A, B and C – EPSG codes 9810, 9829 and 9830 respectively) and two new variants of Mercator projection (variant A and C – EPSG codes 9804 and 1044 respectively). Mercator variant B (EPSG code 9805) was already included before as Mercator projection.


Mercator variants A and B have origin of northings / Y values at the equator. Variant A uses a scale factor at the equator to reduce overall scale distortion and effectively defines two standard parallels that are symmetric around the equator. Variant B takes a standard parallel and effectively forces the scale factor at the equator to be less than one. Variant C is similar to variant B, but with the addition of a latitude of origin. The origin of northings / Y values occurs at the latitude of origin.


The polar stereographic variant A is centered at a pole. The longitude of origin defines which longitude will be going straight “down” from the North Pole or “up” from the “South Pole” towards the middle of the map. A scale factor reduces the overall scale distortion and effectively defines a standard parallel. The variant B is similar to variant A, only that it takes a standard parallel to reduce the overall scale distortion of the projection and results in a scale factor at the pole of less than one. Variant C is similar to variant B, but with the addition of a latitude of origin. The origin of northings / Y values occurs at the intersection of the latitude of origin and the longitude of origin.


Considering the de facto use of the European datum of 1950 (ED50) throughout the oil industry operating in Northern Europe and the North Sea, I thought it would be interesting to explore this datum’s history and how it came to be the first European continent-wide datum. During the research for this project I uncovered a fasinating story of military intelligence during the Second World War. But first we must set the scene and go back to...


European Geodesy at the Turn of the 20th Century

“The first-order triangulation of Europe [was completed] over the last 200 years” (Hough, 1948)

Prior to World War Two (WW2), Europe was divided into a jumble of independent national and sub-national geodetic datums with their own centre point, triangulation networks and ellipsoids only sometimes connecting to their neighbour’s triangulation effort along the borders.


Central Europe during the late 19th to early 20th Century is a prime example of this situation. Within the German Confederation and other German States their existed nearly as many datum’s as there were political entities (e.g. Hannover (Gauss, 1821); Bavaria (Soldner, 1808-1828), Prussia (Schreiber, 1975), Württemberg etc). Each of these states contained a survey office directing surveying activities. One of the attempts to connect various datums was during the First German Reich. The Reiehsdreieeksnetz began in Prussia through the Preußische Landesaufnahme (Prussian State Survey) along the Baltic coast as far as Berlin and Lübesk. This triangulation was continued under orders for the survey of Hannover by King George IV (the Hannover triangulation is known as Hannoversche triangle chain).


These networks had their origin normally at a major observatory such as Greenwich in London, Pulkovo near St. Petersburg and the Pantheon in Paris. Additionally these datums referenced a variety of ellipsoids making transformation calculations difficult. However a common more fundamental problem summarised by Hough (1948), on the original triangulation of Germany, was that...

“…no attempt [was made] to minimize the effect of the deflection of the vertical at the initial station” Hough (1948)

...and therefore errors in position were found at the place of joining to other triangulation networks before any transformation had even been started.

The direction of the vertical is defined by a local plumbline, where a survey instrument is set up to measure the horizontal plane that is exactly perpendicular to the vertical. The ellipsoid normal through the same point is perpendicular to the local tangent to the ellipse. However due to variations of gravity, the two are not necessarily coincident. The difference is called deflection-of-the-vertical.

Other technical issues existed for trying to connect existing triangulations. The connection between the New Triangulation of France (NTF) Datum and the Belgian Datum of 1927 is an example where the connecting of triangulation networks was insufficiently calculated. A calculation was conducted to find the difference in longitudinal values between Brussels and Greenwich. However this was result was not  incorporated in the joining of the triangulation networks and hence left large errors for the connection of the networks.


Germany - An example of “first order triangulation”

Since the formation of the First German Reich after unification in 1871, efforts had been made to standardise triangulation across the country beginning to solve some of the issues mentioned above. However, state military survey organisations within the German army produced uncoordinated products throughout the period up to the end of WW1, perhaps indicating disloyalty within the newly unified country. This lack of coordinatation and communication between survey organisations led to some poor quality mapping products being produced during the First World War (see Cruickshank, 2006 for more details).


After the First World War and the Treaty of Versailles in 1919 a reduction in military staff led to the demilitarisation of survey groups and the establishment of Reichsamt für Landesaufnahme (Reich Office for State Survey) who led an overhaul of Germany's mulitiple triangulations. A “Neutriangulation” of Bavaria, Baden, Württenberg, Silesia, Pomerania, Mecklenburg and Schleswig-Holstein took place in 1925. This “Neutriangulation” can been noted as a geodetic manifestation in the balance of power from the German Provinces.


As political tensions rose during the 1920 – 1930’s, driven in part by the dire economic situation throughout Germany and global depression, extremes in the political arena took hold eventually leading to the events that resulted in the rise of Nazism. Adolf Hitler and the Nazi party took hold of the country via emergency decree on 27th February 1933 after the Reichstag fire.


Development of a Military Survey

After the seizing of power by the Nazi’s Germany no longer cooperated according to the Treaty of Versailles, restoring pre-war military institutions and a 9th Division to the General Staff of the Army, known as the Military Survey (Reichsamt Kriegskarten und Vermessungswesen, see details about the organisation in Cruickshank, 2005). In 1936 Lt. Colonel Hemmerich was appointed Department Chief. Under Hemmerich’s leadership the division dealt with the collection, evaluation, cataloguing and co-ordination of foreign maps and geodetic data, which were collated and reported in the ‘Planhefte’. These became major publications of the German Military Survey.

Hemmerich.pngFigure 1 Lt. Colonel Hemmerich (image from


The development of the military survey coincided with early attempts by the Minister of the Interior to create a A Neuordnung des Vermessungswesens (New Order of Survey and Mapping) and by 1936 Survey Commissars were established throughout the regions of the now Third Reich. These commissars were also the local political leaders of individual states.

“In 1936 the German main triangulation network was readjusted. Since considerable portions were introduced into the readjustment without any modification and since others had not yet been observed completely, the readjustment could be carried out in parts only.”
Hough 1948

An attempt by the German's to create an early equivalent of the European Datum was started in preparation for, and developed throughout,  the Second World War. This was due to the failings of the pre-First World War military survey activity that resulted in poor location plots and the use of old data (see Cruickshank, 2006 for a detailed discussion). During the inter-war period lessons were drawn from the experience of the First World War,  in particular about the importance of collecting up-to-date foreign maps and geodetic data.


With war imminent in August 1939, the Military Survey was mobilized and made ready to be attached to the individual commanding authorities within the Germany Army. These geodetic units followed the German army into field of operations that by 1942 occupied the vast majority of Europe and Northern Africa.


World_War_II_in_Europe%2C_1942.svgFigure 2 Maximum Extent of Nazi Germany during World War 2 (image taken from wikipedia)



From this military position work began on the establishment of a single unified geodetic framework for the whole of continental Europe (including Northern Africa). Hemmerich’s division uniquely had control of nearly every geodetic department in Europe and thus controlled the expansion of a wealth of knowledge and equipment that would allow the Germans to accurately survey Europe. It is this work, carried out by Hemmerich’s division during the Second World War, that sowed the seeds for the creation of the European Datum.


Hemmerich lost his commanding post on 05th April 1945 where he was resigned to the Führerreserve and later arrested and imprisoned by Allied forces until 04 June 1947.


Next time we shall have a look at the development of the European Datum from the side of the allies and explore the story of the military intelligence division code named the HOUGHTEAM.


[1]This discrepancy was one of the major factors that prompted the recomputation of all geodetic control in Western Europe after the First World War. The Bonne Grid “New Convention” is also referred to as the “Orange Report Net Grid” and was used through WWII until 1950.



Cruickshank, J. L., 2005. “The Reichsamt fur Landesaufnahme and the Ordnance Survey (Part 1)”. Sheetlines, 72, pp.9-22

Cruickshank, J. L., 2006. “Kaiser Bill thought he knew where you lived”. Sheetlines, 77, pp.5-20

Hough, F., (1948) The adjustment of European first-order triangulation. Bulletin géodésique 7(1) pp35-41