Stokes parameters of the infinitely compact spots and disk segments. Averaging was made over Δφ = 45° (i.e., a quarter of the circle). The upper and lower panels correspond to the absolute and relative Stokes parameters, respectively. Black, red, and green lines denote calculations of the infinitely small spot, while blue, violet, and yellow lines correspond to the parameters averaged over the segment. Note that several lines overlap in the lower panels.