def get_segment_mid_point(tigl, idx_wing, idx_segment, eta, xsi):
    """
    Return a mid point for a segment

    Args:
        :tigl: Tigl handle
        :idx_wing: Wing index
        :idx_segment: Segment index
        :eta: Relative segment coordinate
        :xsi: Relative segment coordinate

    Returns:
        :mid_point: List with mid coordinate
    """

    lower = tigl.wingGetLowerPoint(idx_wing, idx_segment, eta, xsi)
    upper = tigl.wingGetUpperPoint(idx_wing, idx_segment, eta, xsi)
    mid_point = [(l + u)/2.0 for l, u in zip(lower, upper)]
    return mid_point