Radiometrics Tellus Survey 2005 - 2006 Geophysical data were collected in 2005 and 2006 by the Joint Airborne-geoscience Capability (JAC), a joint venture between the Finnish Geological Survey (GTK) and the British Geological Survey (BGS). Magnetic, electromagnetic and terrestrial gamma-radiation (radiometric) data were recorded. Data were acquired for 80,458 line km of survey. Flight lines were spaced 200 m apart in the direction 165-345 degrees. The survey was flown with a nominal ground clearance of 56 m in rural areas and 240 m in urban areas, with sample intervals of 7 m (magnetics), 17.5 m (electromagnetics) and 70 m (gamma radiation).