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.

The high-resolution airborne surveys shown on the map based index (GeoIndex) are classed as those flown with low terrain clearance (typically below 200m) and flight line spacing of less than 300m. The surveys were flown with various combinations of magnetic, radiometric and EM techniques, and include; Surveys flown for the DTI mineral reconnaissance programme, Commercial surveys flown for mineral exploration and subsequently donated to the BGS and Surveys flown for the BGS for research and other purposes.