“…The theory is grounded firmly in geographic and cartographic abstraction and modeling principles (Peuquet, 1984;Peuquet, 1988;Guptill and others, 1990) and in cognitive category theory (Mark, 1993;Usery, 1993Usery, , 1996Frank, 1998). The theory builds from basic research into the three aspects of geographical entities defined by Berry (1964) and used by many researchers since that time (Sinton, 1978;Usery, 1993Usery, ,1996Peuquet, 1994;Peuquet and Duan, 1995;Yuan, 1996Yuan, , 1999. This research is a unique contribution because the developed theory supports a variety of data types including objects, fields, and objects with field-like properties and multiple applications from a single theoretical structure.…”