  Upcoming microwave background experiments will see an incredible increase in
the volume of data to be analyzed, which makes the choice of how it is
discretized on the sky a crucial issue. I discuss criteria for evaluating
different pixelizations and the advantages of using an exactly azimuthal or
`igloo' pixelization of the sky. Talk given at ``The CMB and the Planck
Mission" workshop in Santander, Spain, June 1998.
