A Computer-Assisted Diagramming System

This research investigates characteristics and generation of graphic diagrams used in support of analysis, presentation and synthesis of information in various domains. The research is aimed at the development of a software system which can be used to specify, generate and manipulate diagrams similar to the way they are represented and operated upon in traditional media.Diagrams are graphic representations of symbolic propositions that allow tentative reasoning and inferencing, and enable a person to focus on selected aspects of a situation that are deemed of interest. The economy and directness of expression found in diagrams seem to be the prime reasons why they are so ubiquitous in many domains. Despite these advantages, studies into supporting diagrammatic representations using computers are rather sparse. This research is an attempt at developing a comprehensive framework of thought in this direction.In the context of design disciplines like architecture, this research forms a part of the continuum of studies in computer aided design techniques and tools. While a large number of tools and techniques in CAD have emerged so far, usage of such tools, due to their underlying representations, expects and demands commitment of too many details too early in the design process. This research is aimed at characterizing and developing a computer based diagramming system to support tentative reasoning using diagrams, and thus hopes to extend the scope of CAD environments in design. The thesis first articulates motivations for this topic in detail. Next, a discussion on the role played by diagrams as conceptual tools in various domains is presented. It is followed by a detailed look at characteristics and components of diagrams viewed as a graphic communication system. Next, a comprehensive set of requirements for an ideal software environment for diagramming tasks is developed. A prototype system called CDT was implemented and is used to demonstrate ideas developed in this research. The study concludes with some observations on contributions of this research effort and possible future extensions