The evolution of thematic cartography - a research methodology and historical review.

The need for methodology and an organizational framework on which research in the history of thematic cartography can be based is presented. A methodology geared to the needs of cartographers is suggested. According to the framework outlined, the evolution of thematic cartography is divided into 3 primary lines of development corresponding to point, line and area symbolization. Within each division, developments are fruther classified according to whether data illustrated are qualitative and whether physical or cultural phenomena are represented. A review of current knowledge, organized according to the framework outlined, is presented as a means of demonstrating the utility of the framework. The use of the framework as a guide to research in the history of thematic cartography is discussed.-Author