Sample C¹⁸O spectra from the MHD model, taken at equidistant positions over the area shown in Fig. 23. The black line shows the synthetic observations with noise equal to σ(T) = 0.05 K. The solid red and dashed blue curves correspond to the SPIF and GaussPy fits, respectively. The number of Gaussian components selected by the methods are indicated in the frames with numbers of the corresponding colour.