# HeadingData
Simple object holding compass heading data.
NOTE
This is an abstract type. Any object of this structure can be used where this type is used.
# Properties
# accuracy
Accuracy of the compass heading, in platform-specific units.
On iOS, accuracy is returned as a maximum deviation in degrees, the smaller the value, the more accurate the heading is. For example, a value of 10 means the heading is plus or minus 10 degrees from the actual value. A negative value indicates the compass heading is invalid; for example, if there is magnetic interference, or if the compass is not calibrated.
On Android, the value is set to either 1 (low accuracy), 2 (medium accuracy) or 3 (high accuracy). No specific definition of these accuracy values is supplied.
# trueHeading
Declination in degrees from true North.
Calculating the true heading requires correcting the magnetic declination based on
the device's current location. So trueHeading
can only be calculated if the device
has a fairly recent location fix. If you want to obtain the true heading, you
should register for location updates as well as compass updates. The location fix
does not need to be very accurate.
On Android, trueHeading
is undefined
if a recent location fix is not available.