Cartographic Data Structures

Efficient and flexible data structures are important to the development of computer mapping. Most current data banks are characterized by 1) structures which' are convenient at the input stage rather than at the stages of use within computer programs, 2) separate and uncoordinated files for different types of geographic feahires, and 3) a lack of information about neighboring entities. The term "neighborhood function" may be used to indicate the relative location of a geographic entity and is a concept which is involved in all three of these characteristics. Ongoing research on data structures had led to work on the GEOGRAF system for encoding planar data and the GDS ("Geographic Data Structure") for encoding three-dimensional surfaces. Both involve data manipulation between the digitizing stage and the actual use of the data within computer mapping programs.