Maps of Log₁₀ of column density (range between 10^-15 g/cm² and 10^-12 g/cm²) seen from two different points of view; superimposed are the cloud of points inferred from the polarization ratio (red crosses) and the cloud of points of the centre of mass along the LOS (light blue crosses) projected on the plane of sky: a) point of view parallel to the y direction and (x,z) coordinates of the clouds of points; b) point of view parallel to the x direction and (z,y) coordinates of the clouds of points.