The heading (measured in degrees) relative to true north.
UIKit for Mac 13.0+Beta
The value in this property represents the heading relative to the geographic North Pole. The value 0 means the device is pointed toward true north, 90 means it is pointed due east, 180 means it is pointed due south, and so on. A negative value indicates that the heading could not be determined.
In iOS 3.x and earlier, the value in this property is always measured relative to the top of the device in a portrait orientation, regardless of the device’s actual physical or interface orientation. In iOS 4.0 and later, the value is measured relative to the heading orientation specified by the location manager. For more information, see the headingOrientation property in CLLocationManager.
This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.