N-PDFs of all clouds ordered by cloud type, from high-mass and intermediate mass SF regions (top panels) to low-mass and quiescent regions (bottom panels). Each panel shows the N-PDFs for clouds in different colors. The column density is expressed in visual extinction (upper x-axis) and in η (lower x-axis). Error bars are calculated using Poisson statistics. For better visibility, we reduced the error bars by a factor of 2 (see figures in Appendix C for plots with the full error bars). We note that recently, a more sophisticated method was proposed by Jaupart & Chabrier (2022) to derive the statistical error bars of PDFs employing the autocovariance function.