PLR Partitions: A Conceptual Model of Maps

The traditional spatial data models model space in terms of points, lines, and regions. These models employ a disjoint dimension model in which a spatial object can only consist of a zero, one, or two dimensional point set. However, such models cannot adequately represent spatial reality. For example, consider a river network that contains both rivers and lakes. Intuitively, this river network is a single object made up of one-dimensional components (the river segments), and two dimensional components (the lakes). Typically, collection types are used to represent such an object, but they present new problems.