The following policy operates under the Library's general policy statements with respect to collection development. The British Library Map Collections, comprising the cartographic holdings of the Map Library as well as maps in other departments, most notably Manuscripts, form what is arguably the finest map collection in the world. Unlike those in other institutions, the BL Map Collections are unparalleled in both historical and modern materials.
Map Library's historical collections concentrate mainly on material with British connections, but in the light of British history, this necessarily covers most of the world at different periods. Antiquarian purchases are made to fill gaps in the collections and a substantial part of the purchase fund is devoted to this purpose. As part of its role as one of the major centres of historical cartographic studies and carto-bibliographical research, Map Library's objectives include the collection of literature about maps and map-making. Modern printing techniques have made it possible to reproduce high-quality facsimiles of older maps, generally accompanied by essential texts written by leading experts, and these are also collected.
Particular strengths are all aspects of British cartography, including Ordnance Survey, early European mapping (from 6th century), portolan charts, European atlases from the 15th century, colonial mapping, military and administrative mapping since the Renaissance, Asian mapping, and modern mapping world-wide.
Current materials are mainly acquired in three different ways. British cartographic publications are received on legal deposit. These are considerable given the output and world-wide reputation of British map publishers. Material is also received from Ordnance Survey Northern Ireland and Ordnance Survey Ireland, and special agreements are in place with the United States Geological Survey and National Imagery and Mapping Administration, the Canadian Department of Mines and Surveys, the Australian National Mapping Authority, and the New Zealand Department of Lands and Surveys.
Second are the materials donated by the Ministry of Defence as part of its programme of distribution of superseded maps and related materials to map collections across the UK. The British Library is by far the largest recipient of such materials, which include medium and large scale foreign topographical and other types of maps mainly of Europe, Asia and Africa. As map production in many countries is not as accessible as it is in the UK and the US, the special acquisition methods and funding available to the MoD make these donations a remarkable collection of 20th-century materials unlikely to be found in other publicly-accessible collections.
Third is a programme of purchases carefully monitored to fill in gaps in receipts from MoD and meet general research needs, which has begun to include materials in digital formats. Such acquisitions are made taking into consideration collection policies in the other major research collections in Britain.
The Map Library maintains its archive of large-scale Ordnance Survey (OS) maps in digital form, as OS stopped producing these maps on paper or fiche in 1999 (annual receipts numbered in the thousands).
Related to, but distinct from our special relationship with the Ministry of Defence is the acquisition of its cartographic archives. This includes compilation material which has been deposited with us at different times since about 1960 and, more recently, the archive of UK military mapping produced by the Ministry of Defence and its predecessors since c.1880. The archive, estimated at about 200,000 sheets, is being deposited as a public record in an arrangement brokered by the Public Record Office.