Digital Sky Surveys from the ground: Status and Perspectives
  I first review the status of Digital Sky Surveys. The focus will be on
extragalactic surveys with an area of more than 100 sq.deg. The Sloan Digital
Sky Survey is the archetype of such imaging surveys and it is its great success
that has prompted great activity in this field. The latest surveys explore
wider, fainter and higher resolution and also a longer wavelength range than
SDSS. Many of these surveys overlap particularly in the S Hemisphere where we
now have Pan-STARRS, DES and the ESO VST surveys, and our aim here is to
compare their properties. Since there is no dedicated article on the VST ATLAS
in this symposium, we shall especially review the properties of this particular
survey. This easily fits onto our other main focus which is to compare
overlapping Southern Surveys and see how they best fit with the available NIR
imaging data. We conclude that the Southern Hemisphere will soon overtake the
North in terms of multiwavelength imaging. However we note that the South has
more limited opportunities for spectroscopic follow-up and this weakness will
persist during the LSST era. Some new perspectives are offered on this and
other aspects of survey astronomy.
