An experiment was conducted on navigation through three-dimensional visualizations of document databases. Subjects navigated through a 1000-document information space in which documents near each other were likely to be about a similar topic and keywords displayed in the space indicated the topic of nearby documents. The influence of frame of reference and use of a map on document search and spatial judgment tasks was investigated. The frame of reference distinction compared a more egocentric (inside-out, immersed) perspective and a more exocentric (outside-in, bird's eye) perspective. Performance was best with the exocentric display, with the egocentric display a close second. Use of a map hindered rather than supported performance. Results revealed tool/strategy choice as an important mediator of the influence of frame of reference, with non-optimal tool choices observed. Spatial ability correlated with performance. Results are accounted for in terms of mediating influences.