The three files Galicia_lead.data, Galicia_poly.data and Galicia_boundary.data relate to a study of atmospheric pollution undertaken in Galicia, north-east Spain in 1997. Galicia_lead.data Data on measured lead concentrations in moss samples taken at 63 locations Results from each sampling location are presented as x distance east of arbitrary origin (kilometres) y distance north of arbitrary origin (kilometres) z measured lead concentration Galicia_poly.data Approximate digitised boundary of Galicia: x distance east (kilometres) y distance north (kilometres) Galicia_boundary.data More accurate digitised boundary of Galicia: x distance east (kilometres) y distance north (kilometres) NOTE: computations involving the boundary of a spatial region specified as an irregular polygon can be slow when the polygon has many vertices. The polygon stored as the file Galicia_poly.data is adequate for statistical analysis; the polygon stored as the file Galicia_boundary.data is aesthetically more pleasing.