The FWHM values of the twelve filaments. The frames a)–c) correspond to the models A–C, respectively. The squares and the triangles correspond to the near cloud distance of 93 pc and the medium cloud distance of 186 pc, respectively. The solid symbols are values derived from N^True and the open symbols values from N^Obs. The dashed lines indicate the median values for the FWHM values derived from N^Obs. Upper line corresponds to the distance of 186 pc and lower line to the distance of 93 pc.