Date of Award

Spring 2004

Project Type


Program or Major

Computer Science

Degree Name

Doctor of Philosophy

First Advisor

Colin Ware


The central question behind this dissertation is this: In what ways can 3D multiscale spatial information be presented in an interactive computer graphics environment, such that a human observer can better comprehend it? Toward answering this question, a two-pronged approach is employed that consists of practice within computer user-interface design, and theory grounded in perceptual psychology, bound together by an approach to the question in terms of focus and context as they apply to human attention. The major practical contribution of this dissertation is the development of a novel set of techniques for linking 3D windows to various kinds of reference frames in a virtual scene and to each other---linking one or more focal views with a view that provides context. Central to these techniques is the explicit recognition of the frames of reference inherent in objects, in computer-graphics viewpoint specifications, and in the human perception and cognitive understanding of space. Many of these techniques are incorporated into the GeoZui3D system as major extensions. An empirical evaluation of these techniques confirms the utility of 3D window proxy representations and orientation coupling. The major theoretical contribution is a cognitive systems model that predicts when linked focus and context views should be used over other techniques such as zooming. The predictive power of the model comes from explicit recognition of locations where a user will focus attention, as well as applied interpretations of the limitations of visual working memory. The model's ability to predict performance is empirically validated, while its ability to model user error is empirically founded. Both the model and the results of the related experiments suggest that multiple linked windows can be an effective way of presenting multiscale spatial information, especially in situations involving the comparison of three or more objects. The contributions of the dissertation are discussed in the context of the applications that have motivated them.