  Spatial data mining or Knowledge discovery in spatial database is the
extraction of implicit knowledge, spatial relations and spatial patterns that
are not explicitly stored in databases. Co-location patterns discovery is the
process of finding the subsets of features that are frequently located together
in the same geographic area. In this paper, we discuss the different approaches
like Rule based approach, Join-less approach, Partial Join approach and
Constraint neighborhood based approach for finding co-location patterns.
