  The results obtained from a study of the mass distribution of 36 spiral
galaxies are presented. The galaxies were observed using Fabry-Perot
interferometry as part of the GHASP survey. The main aim of obtaining high
resolution H alpha 2D velocity fields is to define more accurately the rising
part of the rotation curves which should allow to better constrain the
parameters of the mass distribution. The H alpha velocities were combined with
low resolution HI data from the literature, when available. Combining the
kinematical data with photometric data, mass models were derived from these
rotation curves using two different functional forms for the halo: an
isothermal sphere and an NFW profile. For the galaxies already modeled by other
authors, the results tend to agree. Our results point at the existence of a
constant density core in the center of the dark matter halos rather than a
cuspy core, whatever the type of the galaxy from Sab to Im. This extends to all
types the result already obtained by other authors studying dwarf and LSB
galaxies but would necessitate a larger sample of galaxies to conclude more
strongly. Whatever model is used (ISO or NFW), small core radius halos have
higher central densities, again for all morphological types. We confirm
different halo scaling laws, such as the correlations between the core radius
and the central density of the halo with the absolute magnitude of a galaxy:
low luminosity galaxies have small core radius and high central density. We
find that the product of the central density with the core radius of the dark
matter halo is nearly constant, whatever the model and whatever the absolute
magnitude of the galaxy. This suggests that the halo surface density is
independent from the galaxy type.
