I am wondering how compass calibration works / why e.g. drawing
an 8 or rotating the phone to all 3 axis works (or at least
shall work) - I mean I would understand the calibration process,
if an application would say me: Point to north, then press that
button down there, but you can start at basically zero knowledge
for the app, just by rotating your phone! How is that done?
Also, do I need to enter a special calibration mode or can I
draw these figures (like the 8) directly in Google Maps? How
does Google Maps know that I am not just really moving the phone
but want to calibrate the compass? Thanks for any hint! Compass
calibration works by detecting the magnetic field intensity of
earth. But sometimes due to strong interference from other
electronic devices like transformers compass sensor may get
wrong idea about the magnetic poles of earth and can point in
wrong direction. So to ensure that it asks users to recalibrate
compass by rotating in figure 8 direction so that it can judge
the magnetic intensity i