Can someone tell me is it possible to extract the magnetic variation / declination from the N8? The Qt API (QGeoPositionInfo::hasAttribute(MagneticVariation)) is telling me that this attribute is not available. If that's the case, then so be it, but I'd like to check that I'm not doing something wrong if the variation should actually be available.

I'm also curious about the magnetic variation / declination in general: on models where it is available, how is it obtained? Is it provided via the GPS, based on a model?

If it's not available, why not? - what prevent it being available on certain models?