  Here we explore the impact of all major factors, such as the non-homogeneous
gas distribution, galactic rotation and gravity, on the observational
appearance of superbubbles in nearly face-on spiral galaxies. The results of
our 3D numerical simulations are confronted to the observed gas column density
distribution in the largest South-East superbubble in the late-type spiral
galaxy NGC 628. We make use of the star formation history inside the bubble
derived from the resolved stellar population seen in the HST images to obtain
its energy and demonstrate that the results of numerical simulations are in
good agreement with the observed gas surface density distribution. We also show
that the observed gas column density distribution constraints the gaseous disk
scale height and the midplane gas density if the energy input rate could be
obtained from observations. This implies that observations of large holes in
the interstellar gas distribution and their stellar populations have the
potential power to solve the midplane gas density - gaseous disk scale-height
degeneracy problem in nearly face-on galaxies. The possible role of
superbubbles in driving the secondary star formation in galaxies is also
briefly discussed.
