  We have used Virtual Observatory technology to analyse the disk scale length
and central surface brightness for a sample of 29955 bright disk galaxies from
the Sloan Digital Sky Survey. We use the results in the r-band and revisit the
relation between these parameters and the galaxy morphology, and find the
average disk surface brightness of 20.2(0.7) mag/arcsec^2. We confirm that late
type spirals populate the lower left corner of the scale length-mu0 plane and
that the early and intermediate spirals are mixed in this diagram, with disky
ellipticals at the top left corner. We further investigate the Freeman Law and
affirm that it indeed defines an upper limit for the disk central surface
brightness in bright galaxies, and that disks in late type spirals have fainter
central surface brightness. Our results are based on a volume corrected sample
of galaxies in the local universe (z < 0.3) that is two orders of magnitudes
larger than any sample previously studied, and deliver statistically
significant implications that provide a comprehensive test bed for future
theoretical studies and numerical simulations of galaxy formation and
evolution.
