DIAGONAL DISPLAY - A NEW TECHNIQUE FOR GRAPHIC REPRESENTATION OF COMPLEX TOPOLOGICAL NETWORKS.

A new method has been developed for automatically drawing diagrams of topological networks containing a large number of interconnected nodes representing interrelated items, concepts, or events. The method allows a display of at least 100 nodes, permits an unlimited number of interconnections among nodes, is algorithmically manipulable, and is felt to be simple and aesthetically pleasing. Many known techniques for automatically drawing networks or graphs were reviewed, including those used in computer flow charting, electric circuit drawing, logical analysis, etc. A series of formats for displaying topological networks was tried, including a new format called Diagonal Display. This involves drawing nodes in a diagonal array and showing interconnections by rectangular lines in the adjacent areas. The upper or lower elbows of the lines for connecting edges fall into positions which correspond to the coordinates of a matrix representation of the network. To implement the automatic display by a computer-activated pen plotter, a program was written for a system employing an IBM 1401 computer and a Calcomp 563 plotter. The original impetus for this study was the need to display networks of bibliographic citations used in historical research or in searching scientific and technical literature. Other applications are also considered, including PERT diagrams, organizational charts, etc.