Frame of reference and navigation through document visualizations

The rate at which data and documents are being generated has reached such high levels that the problems surrounding managing and accessing information have been termed "information overload." Traditional approaches to information access such as querying have not proved fully adequate. In the research presented here, an alternative to querying, information space navigation, was investigated. In information space navigation, users interact with a three-dimensional visualization of a set of documents. An information space was developed for the experiment in which close to 1000 documents were presented in three dimensional space, such that, overall, documents near to each other were likely to be about a similar topic and nearby keywords displayed in the space indicated the topic of nearby documents. The advantages of use of a spatial representation are presented, along with a review of relevant research and theory on spatial cognition.; The current research focused on the influence of frame of reference on search and judgment tasks using an information space. The frame of reference distinction describes the location and stability of the user's viewpoint and varies between a more egocentric (inside-out, immersed) perspective and a more exocentric (outside-in, bird's eye) perspective. The role of using a map to support use of an egocentric perspective was also examined. The tasks involved searching for particular documents or making judgments about the spatial arrangements of documents. The displays were hypothesized to influence performance due to a small number of mediating influences (e.g., the keyhole effect in which only a portion of the space is visible at one time with an egocentric perspective).; Results indicated that the exocentric perspective was the best overall for the tasks examined. The egocentric perspective was a close second (perhaps because backing up still allowed a more exocentric view), but showed some evidence of being hindered by ambiguity along the line of sight. The impact of staticness, the lack of benefit of consistency, and the influence of the keyhole effect on strategy choice are explored. Strikingly, the provision of a map display did not improve use of an egocentric view, instead slowing performance for a couple of the tasks. This result is attributed to demands for integrating the two views of the space.; The data revealed a strong influence of spatial ability on performance, suggesting that information navigation is more difficult for those with lower spatial ability. Tool and strategy choice likely played a role in the high variability observed in the data, but the flexibility allowed subjects in the current paradigm strengthens the generalizability of the findings. Finally, subjects did not always adjust their tool usage optimally depending on performance, instead an overuse of the map was observed. The implications of the findings for system design are described (supporting the use of an exocentric perspective and suggesting caution in the use of maps) and several future lines of research are presented.