Top panel shows the estimated distance profiles of Feature 2, based on application of the PP, FP, HM and SSE methods based on elongation-time variations estimated from STEREO-A J-maps. In the bottom panel, speed profiles derived from the adjacent distances using 3-point Lagrange interpolation (solid line shows the polynomial fit) are shown. Vertical lines show the error bars, derived by taking uncertainties of 3% and 4% in the estimated distance in the HI1 and HI2 fields of view, respectively.