Notes. Each label (R1, R2, etc.) corresponds to the full data set (Spitzer, Herschel and gas maps), but with different pixel sizes. The resolution R10 corresponds to the integrated strip; it is a rectangle. That is the reason why there are two dimensions. In the text, we will refer to the geometric mean of these two dimensions. The three columns on the right side of the table list the number of pixels. The first (“total”) is the total number of pixels in the map, at a given resolution. The second (“dust modelling”) is the number of pixels used for the dust modelling. It is the total number of pixels in the maps minus the pixels which give bad fits at R1. When building lower resolution maps, we exclude these bad pixels. Consequently, for a given waveband, the sum of the pixel fluxes is rigorously the same at all spatial resolutions. The third number (“comparison to H i and H₂”) is the number of pixels used when comparing the dust and gas properties. Since the ¹²CO(J = 1 → 0)_2.6   mm map is not defined on the entire strip, it corresponds to a smaller number of pixels.