N-PDFs obtained from the various column density maps. Left: N-PDF of the high-res N_H column density map derived using all Herschel dust data employing method I only for non-blanked pixels of Fig. 4. Right: N-PDF of the N_H column density map derived with method II for the same non-blanked pixels of Fig. 4. The green lines show the N-PDF of H I. Here, η is defined by $\eta =ln\frac{N}{⟨N⟩}$, where N is the column density and ⟨N⟩ the mean column density.