The �Third Dimension�
Galaxy distributions seen in images are 2-d
projections on the sky.
Need distances�easiest way is to use the
Hubble flow and redshifts, either
photometric or spectra (best).
Reminder � SDSS and 2dF rule here now.
Huchra and Gellar�s �Z-machine� for the
CfA survey as recounted in �Lonely Hearts
of the Cosmos� by Dennis Overbye � Great!