Left: ∫ τdv (MALS) versus N_HI (HI4PI; blue dots) or $N_{\mathrm{H}\mathrm{I}}^{\text{ext\hspace{0.17em}}}=A_{\mathrm{V}}[\mathrm{m}\mathrm{a}\mathrm{g}]\cdot 2.21\times {10}^{21}{\mathrm{c}\mathrm{m}}^{-2}$ (yellow dots; based on Eq. (6)) is plotted on a double logarithmic scale. The two regression lines, both with correlation coefficients of 0.89 and 0.85 respectively, are plotted as dashed and dash-dotted lines (see text for details). The error bars on H I column density correspond to HI4PI 3σ detection levels, whereas the error bars in the y direction are based on uncertainties in tau_int_val. Right: T_Spin (see Eq. (7)) versus A_V on a double logarithmic scale. The dashed and dash-dotted lines mark the range of uncertainty by fitting a linear function to the data values. The dashed red line represents the average of both least-square approximations.