  As a part of a Euro-VO research initiative, we have undertaken a programme
aimed at studying the scale length of 54909 Sa-Sd spiral galaxies from the SDSS
DR6 catalogue. We have retrieved u,g,r,i,z-band images for all galaxies in
order to derive the light profiles. We also calculate asymmetry parameters to
select non-disturbed disks for which we will derive exponential disk scale
lengths. As images in different bands probe different optical depths and
stellar populations, it is likely that a derived scale length value should
depend on waveband, and our goal is to use the scale length variations with
band pass, inclination, galaxy type, redshift, and surface brightness, in order
to better understand the nature of spiral galaxies.
