N-PDFs of LOS corrected column density (blue points), expressed in visual extinction (upper x-axis) and in η (lower x-axis) of DR21 (left) and DR15 (right). The left y-axis gives the PDF (there can be small differences compared to the plots in Appendix C because for the model fit, we excluded the extreme low- and high density ranges, which leads to a slightly different normalization). The orange curve indicates the best fitting model for the N-PDF (see Table B.1 and B.2). The vertical lines show the peak values of the log-normal(s) in blue, the break points for the power laws in orange and the error power law break point in green. Underneath is the standardized residuals, a perfect model would give numbers with mean of 0 and a variance of 1.