  Not only source catalogs are extracted from astronomy observations. Their sky
coverage is always carefully recorded and used in statistical analyses, such as
correlation and luminosity function studies. Here we present a novel method for
catalog matching, which inherently builds on the coverage information for
better performance and completeness. A modified version of the Zones Algorithm
is introduced for matching partially overlapping observations, where irrelevant
parts of the data are excluded up front for efficiency. Our design enables
searches to focus on specific areas on the sky to further speed up the process.
Another important advantage of the new method over traditional techniques is
its ability to quickly detect dropouts, i.e., the missing components that are
in the observed regions of the celestial sphere but did not reach the detection
limit in some observations. These often provide invaluable insight into the
spectral energy distribution of the matched sources but rarely available in
traditional associations.
