global radioTierra    # radio de la tierra en km
radioTierra = 6372.8

function Haversine(lat1, long1, lat2, long2 , radio)
	d_long = radians(long1 - long2)
	theta1 = radians(lat1)
	theta2 = radians(lat2)
	dx = cos(d_long) * cos(theta1) - cos(theta2)
	dy = sin(d_long) * cos(theta1)
	dz = sin(theta1) - sin(theta2)
	return asin(sqr(dx*dx + dy*dy + dz*dz) / 2) * radio * 2
end function

print
print " Distancia de Haversine entre BNA y LAX = ";
print Haversine(36.12, -86.67, 33.94, -118.4, radioTierra); " km"
end