A Well-Known Text (WKT; see http://en.wikipedia.org/wiki/Well-known_text) representation of the the shape (footprint) that defines the location of the occurrence. Example: the one-degree boundin box with opposite corners at (longitude=10, latitude=20) and (longitude=11, latitude=21) would be expressed in well-known text as POLYGON ((10 20, 11 20, 11 21, 10 21, 10 20))