Line-of sight velocity across the filament derived from C¹⁸O(2–1) emission averaged along the filament as a function of the distance (r) for the northern (red) and southern (green) maps. The distance is always determined perpendicular to the local orientation of the filament crest center. The horizontal dashed lines indicate the velocity at the center of the filament crest, the vertical dashed line indicates the center of the crest, and the errorbars indicate the dispersion at each radius in the maps.