Comparison of Doppler velocity (left panel) and line-of-sight projected LCT velocity (right panel). The green contours outline the absolute radial magnetic field at 10 Gauss. The dark and bright red contours indicate the umbral and penumbral boundary, respectively. The orange shaded region in the right panel indicates the region that is excluded in the following (see text for details). The red line in the left panel indicates the position of the line plot in Fig. B.2. The axis labels are in Carrington coordinates. The center of the maps is approximately 23° from disk center, which is in the direction toward the upper left corner.