How to correctly calibrate my compass ?
If you notice that 
isn’t displaying exactly what you are looking at, then you need to calibrate your compass.
This is a common problem for all application relying on a compass and it is due to the sensitivity of digital magnetometers to external magnetic fields. Your device will eventually propose you to calibrate but it might take some time before this happens.
To get the best of , we suggest that you slowly rotate your device as seen in the illustrations below. Switching the compass off and then on again will also help.
