  We present a detailed study of the Galaxy Evolution Explorer's photometric
catalogs with special focus on the statistical properties of the All-sky and
Medium Imaging Surveys. We introduce the concept of primaries to resolve the
issue of multiple detections and follow a geometric approach to define clean
catalogs with well-understood selection functions. We cross-identify the GALEX
sources (GR2+3) with Sloan Digital Sky Survey (DR6) observations, which
indirectly provides an invaluable insight about the astrometric model of the UV
sources and allows us to revise the band merging strategy. We derive the formal
description of the GALEX footprints as well as their intersections with the
SDSS coverage along with analytic calculations of their areal coverage. The
crossmatch catalogs are made available for the public. We conclude by
illustrating the implementation of typical selection criteria in SQL for
catalog subsets geared toward statistical analyses, e.g., correlation and
luminosity function studies.
