public static float difference(final float from, final float to) {
        return normalize(to - from + 180) - 180;
    }
Return the angle to turn of to go from an angle to the other

@param from the origin angle in degrees
@param to   the target angle in degrees
@return a value in degrees, in the [-180, 180[ range
main/src/main/java/cgeo/geocaching/utils/AngleUtils.java