GeolocationCoordinates
The GeolocationCoordinates interface represents the position and altitude of the device on Earth, as well as the accuracy with which these properties are calculated. The geographic position information is provided in terms of World Geodetic System coordinates (WGS84). Available only in secure contexts.
Properties
The altitudeAccuracy read-only property of the GeolocationCoordinates interface is a strictly positive double representing the accuracy, with a 95% confidence level, of the altitude expressed in meters. This value is null if the implementation doesn't support measuring altitude.
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.
The longitude read-only property of the GeolocationCoordinates interface is a number which represents the longitude of a geographical position, specified in decimal degrees. Together with a timestamp, given as Unix time in milliseconds, indicating a time of measurement, the GeolocationCoordinates object is part of the GeolocationPosition interface, which is the object type returned by Geolocation API functions that obtain and return a geographical position.