This layer of the map based index (GeoIndex) shows unadjusted ship gravity, magnetic and bathymetry data acquired by BGS as part of its Offshore Reconnaisance Mapping Programme. This programme commenced in 1967, and was funded mainly by the Department of Energy. Unadjusted ship gravity and bathymetry data from various commercial and academic surveys between 1965 and 1994. Confidential M.O.D Hydrographic Office integrated ship gravity and magnetics surveys of NW Europe marine areas for which BGS acts as agent. Network adjusted gravity and magnetic compilations of data from BGS and non-BGS sources.

The surveys shown on the map based index (GeoIndex) include; Analogue airborne magnetic surveys of Great Britain for the Geological Survey (GSGB), commercial analogue survey of North Sea by Aeroservices Inc, subsequently digitised by BGS, commercial digital (+ one analogue) surveys off NW/N/NE of Britain by Huntings Geology and Geophysics, purchased outright by BGS and Local surveys, digital and analogue aeromagnetic (+ other methods) surveys for BGS and commercial companies.

Digitised version of aeromagnetic survey records of Great Britain comprising a record for each digitised point, supported by survey and 'ends and bends' based line indexes. Original records include flight line records, worksheets, contour sheets and air photos provided by contractors at completion of each survey. Worksheets digitised by BGS during 1980's Smith and Royles 1989.