Ordnance Survey International

The agency In 1946 the Directorate of Colonial Surveys (DCS) was established by the Colonial Office to provide a central survey and mapping organisation for British colonies and protectorates. In 1991, following completion of the last significant aid-funded mapping projects, its name was changed one final time to Ordnance Survey International and its main activity became consultancy, primarily in Eastern Europe. Since 2012, the archive has been held within the National Collection of Aerial Photography (NCAP), and includes some 1.7 million aerial photographs alongside cover traces, maps and annual reports. Having rescued the collection from the defunct British Empire and Commonwealth Museum, NCAP are now cataloguing and digitising the collection. In 2014, a 16-minute Scottish Documentary Institute film entitled 'Sightlines' used photography from the collection to explore the legacy of 20th century aerial survey in Mwatate, Kenya. The film was created as part of Creative Scotland's 'Culture 2014' programme, and premiered at the Edinburgh International Film Festival. To date, a small amount of material from the collection has been made available via the NCAP website, primarily relating to the 2014 documentary. Examples of photography from the collection are also displayed, showing the types of terrain and remote communities which were mapped for the first time by DOS. ==Mapping==

During its lifetime the agency provided mapping to almost all the British colonies and protectorates. Agency surveyors were sent abroad to establish horizontal and vertical ground control for the photography; this was permanently marked and co-ordinated so that the surveys could be the basis for future work. After a map was compiled from the photography, a plot (draft) was made for checking and annotation by the local survey department of the country concerned. The final map was drawn at agency headquarters and printed by the Ordnance Survey. ==Other roles==

In addition to its primary map making role the agency was responsible for: • Provision of advice to the Overseas Development Agency and foreign governments and organisations on technical matters concerning all aspects of surveying and mapping. • Dissemination of information about new techniques related to surveying, photogrammetry, and cartography. ==Directors General==