Directorate of Overseas Surveys (DOS)

  • Scope and Contents: 1.4 million aerial photographs with associated sortie plots, cover traces, card indexes, base maps, contracts, calibration certificates covering 55 countries.
  • Conditions Governing Access:  Largely uncatalogued. Catalogued imagery is accessible on the NCAP website. 



NCAP became the official custodian of 1.5 million aerial photographs created for the Directorate of Overseas Surveys (DOS) in late 2012. Established after the Second World War, DOS was responsible for mapping those parts of the British Empire, and latterly the Commonwealth, which had no survey capability of their own. DOS contracted wide ranging aerial surveys of each country, to provide a basis for cartography. In turn, the cartography and aerial images helped to inform the development and administration of each country.


Flown during peacetime, DOS aerial photography covers large parts of Africa, the Far East, and the islands of the Caribbean Sea, Atlantic and Pacific Oceans. The photography provides a unique historical perspective and is in effect a 'Doomsday Book' of the Commonwealth. The 3D aerial photography in the DOS Collection records the changing urban and rural landscape of large parts of the Commonwealth throughout the second half of the 20th century.





Mapping the World



The DOS was founded by the Colonial Office in 1946 and it existed for 38 years before being merged with the Ordnance Survey in 1984. During its years of service, the Directorate's officers, based in suburban Tolworth in south-west London, were charged with two key tasks:


  • Provide national geodetic frameworks throughout the British Empire that would contribute to understanding the size and shape of the earth and constitute the basis for accurate mapping;
  • Produce mapping using modern methods, based on aerial photography


When the Colonies moved to independence, the remit of DOS was expanded to include countries within and outwith the Commonwealth, which meant the Directorate's surveyors ultimately surveyed fifty-five countries around the world. These included countries in Australasia and the Far East, the Indian Subcontinent, Middle East, Africa, Caribbean, South America, British Antarctic Territory and islands in the Pacific, Atlantic and Indian Oceans and the Mediterranean Sea. Aerial photography of each country was contracted from a variety of commercial survey firms and exploited by staff at Tolworth and in the field.



Examples of DOS imagery

Aerial photography flown for DOS enabled remote and difficult terrain to be mapped for the first time. In addition, the aerial photography survives as a snapshot of each country, its terrain, infrastructure and resources. The image at right illustrates the karst limestone geology of central Jamaica. NCAP-000-000-204-817
The image at right illustrates the isolated nature of communities in some areas of the Commonwealth; here, narrow tracks lead into a remote village in eastern Nigeria where subsistence agriculture sustains the local population. DOS mapping allowed state governments to plan the future development of their country's economy and growth. NCAP-000-000-204-517
In Kenya, wide swathes of land were enclosed into plantations, where one type of crop is grown for an external market. Here, sisal plantations stretch across the landscape south-east of Nairobi. Sisal is a plant native to Mexico, imported to Kenya to be grown commercially; its leaves are sold to make rope, paper and carpets. NCAP-000-000-205-995



After merging into the Ordnance Survey in 1984, the organisation became known as the Overseas Surveys Directorate. In 1991, following completion of the last significant aid-funded mapping projects, its name changed one last time, to Ordnance Survey International, and its main activity became consultancy, primarily in eastern Europe.


Following closure in 2001, responsibility for the records created by DOS was passed to The National Archives. The following year the 1st Print Library, definitive finding aids and air photo mosaic collection were transferred from Ordnance Survey International to the British Empire and Commonwealth Museum, Bristol, and then in 2012 they were deposited with NCAP


A small amount of DOS aerial photography was catalogued and digitised during work on a film project in 2014 and is now online. Further work on this collection will be undertaken when resources permit. At the moment, it is not possible to search within this collection for aerial photography of specific geographic locations, other than those already uploaded to the website. View online DOS images



Related Links


View Directorate of Overseas Surveys images.


Read our feature on Mapping the World