An experimental spatial information system
Computer representation of the continuous two-dimensional features on a map is complicated by the spatial properties not found in typical alphanumeric data. We have designed an entity-oriented relational system for representing the cartographic data, using the concept of spatial data structures. Each geographic entity such as a region, road, or city is represented by a set of relations describing its properties, its related entities, and all the relationships among them. The thesis presents the description of the first experimental cartographic information system based on these concepts to store and retrieve watershed data for a portion of the Wise county in the state of Virginia. The thesis describes the logical structure of the database, the physical structures in memory and on the dist, a guery language interpreter which is used to access the information in the database, and a memory management scheme to transfer the structures back and forth between memory and secondary device.