question: public static long distance ( double latitude1 , double longitude1 , double latitude2 , double longitude2 ) { double latitudeSin = Math . sin ( Math . toRadians ( latitude2 - latitude1 ) / 2 ) ; double longitudeSin = Math . sin ( Math . toRadians ( longitude2 - longitude1 ) / 2 ) ; double a = latitudeSin * latitudeSin + Math . cos ( Math . toRadians ( latitude1 ) ) * Math . cos ( Math . toRadians ( latitude2 ) ) * longitudeSin * longitudeSin ; double c = 2 * MathUtil . atan2 ( Math . sqrt ( a ) , Math . sqrt ( 1 - a ) ) ; return ( long ) ( 6378137 * c ) ; }
target:  Returns the distance between 2 points in meters