Something’s happening to Magnetic North in Great Britain in 2014 by Susan Macmillan on January 31, 2014 BGS geomagnetism grid north magnetic north map north north Susan Macmillan True North +
How do smartphones work out what direction they are pointing? by Ciaran Beggan on November 14, 2013 BGS Ciaran Beggan geomagnetism gravity field magnetic field NOAA smartphone Swarm True North WMM +
