Column density along the z-axis (left panels) and along the y-axis (right panels) for MHD run C1 (upper panels) and hyrodynamical run C2 (lower panels). The left panels illustrate the complex multi-phase structure of the galactic plane, while the right panels show the stratification induced by the gravitational field of the galaxy. In the hydrodynamical run, the interstellar medium is more fragmented than in the MHD one.