Polygon sets consist of three or more coordinates which form a closed loop. They are functionally very similar to the polygons in ArcGIS. A single polygon consists of a series of points connected in order; it is assumed that the last point in the series connects back to the first. A polygon set may contain multiple polygons; these can be positive space or negative space, thus a negative space polygon contained within a positive space polygon indicates a hole. Currently polygons have limited use in PASSaGE but have been added for future expansion.