Example lines of sight using real data in a 15^′ by 15^′ pixel towards prestellar cloud candidates (Planck Collaboration XXVIII 2016). Clockwise from the top left, the panels show one detected cloud (l = 9.25, b = −0.2), two detected clouds (l = 17.2, b = −1.5), no detections (l = 215, b = 4.1), and finally one detected cloud with only an upper limit for the distance (l = 159.7, b = −0.9). Symbols and line styles are as in Fig. 2. The fields shown here were chosen to sample different environments and are not all in the final footprint of the map presented in this paper.