What does this mean? Well we use a mathematical model from those good people at NOAA as the basis of calculating magnetic and secular variation. Every few years an updated data set is published which we need to incorporate into our code. Once we have done some checks and verified that the calculations are correct then we can release the new data set into our products. This affects the UKHO ADP products (although not until next year), the POLAR enterprise editing suite, Henry our flagship navigation system and of course Nuno™ our newly launched small craft navigation system. Rumour has it that something to do with the earth’s magnetic field, the moon and a Windows Phone will be happening here quite soon.
This pic is from http://www.ngdc.noaa.gov/geomag/WMM/image.shtml