Galaxies exhibit a range of morphologies that reflect, at least in part, basic structural differences, such as the presence of disks, spheroids and bars, as well as differences in the visibility of the spiral arms due to for instance to the rate of star-formation.

Although on scales larger than  ~100 Mpc/h the universe is homogeneous and  isotropic,  on smaller scales  structures  in  the universe  are organised hierarchically. The  large scale structures cover a broad range in (over)-density values, physical scales and geometrical shapes. The reconstruction of the density field from an observed galaxy sample should ideally preserve ...