Comparison between Si I 10 827 Å LOS velocity maps of the height-dependent bisectors method and LOS maps of the simulation snapshot transformed to optical depth. The filled circles depict the highest correlation for each bisector map at a given line depth. The dashed line illustrates the linear fitting between all the bisectors (black dots). The red filled circle designates the results from the line-core fit using a second-order polynomial. Uncertainty bars indicate the optical depths where the correlation is higher than 90% for each bisector level.