The maximum deviation (measured in degrees) between the reported heading and the true geomagnetic heading.
- iOS 3.0+
- macOS 10.7+
- Core Location
A positive value in this property represents the potential error between the value reported by the
magnetic property and the actual direction of magnetic north. Thus, the lower the value of this property, the more accurate the heading. A negative value means that the reported heading is invalid, which can occur when the device is uncalibrated or there is strong interference from local magnetic fields.