def METHOD_NAME(self, lon1, lat1, alt1, lon2, lat2, alt2):
    r_earth = 6371000
    lon1, lat1, lon2, lat2 = map(math.radians, [lon1, lat1, lon2, lat2])
    dlon = lon2 - lon1
    dlat = lat2 - lat1
    a = math.sin(dlat/2)**2 + math.cos(lat1) * math.cos(lat2) * math.sin(dlon/2)**2
    c = 2 * math.asin(math.sqrt(a))
    d = c*r_earth
    return math.sqrt(d**2+(alt1 - alt2)**2)