heading
The heading read-only property of the GeolocationCoordinates interface is a double representing the direction in which the device is traveling. This value, specified in degrees, indicates how far off from heading due north the device is. 0 degrees represents true north, and the direction is determined clockwise (which means that east is 90 degrees and west is 270 degrees). If GeolocationCoordinates.speed is 0 or the device is not able to provide heading information, heading is null.