Maps of the N_{H i} column densities (in cm^-2) and W_CO line intensities (in K km s^-1) obtained for different velocity components in the analysis region: N_{H i} for the intermediate velocity arc; N_{H i} and W_CO for the local Chamaeleon complex; and N_{H i} for the Galactic disc background. The N_{H i} column densities have been obtained for optically thin emission. The solid black contour marks the analysis region. The dashed rectangles outline the boundaries of the five substructures described in Sect. 2.5 and analysed in Sect. 10.