import math


def elevation(obj_pos):
    """
    Return elevation angle of an object:
    https://en.wikipedia.org/wiki/Spherical_coordinate_system. Used to determine
    an objects center in y-direction (more to the top or bottom in the image)
    """
    angle = math.atan2(obj_pos[1], -obj_pos[2])
    return math.degrees(angle)