OsmAndLocationProvider.java 文件源码

private float calcGeoMagneticCorrection(float val) {
    if (previousCorrectionValue == 360 && getLastKnownLocation() != null) {
        OsmLocation l = getLastKnownLocation();
        GeomagneticField gf = new GeomagneticField((float) l.getLatitude(), (float) l.getLongitude(), (float) l.getAltitude(),
                System.currentTimeMillis());
        previousCorrectionValue = gf.getDeclination();
    }
    if (previousCorrectionValue != 360) {
        val += previousCorrectionValue;
    }
    return val;
}