Enhancing data exploration with a branching history of user operations

Backtracking and investigating alternative scenarios are integral parts of exploratory data analysis. Yet today's interfaces cannot represent alternative exploration paths as a branching history, forcing the user to recognize conceptual branch points in a Linear history. Further, the interface can only show information from one state at a time, forcing users to rely on memory to compare scenarios. Our system includes a tree-structured visualization for navigating across time and scenarios. The visualization also allows browsing the history and selectively undoing/redoing events within a scenario or across scenarios. It uses the AI formalism of contexts to maintain multiple, possibly mutually inconsistent, knowledge base states. Cross-context formulas can be written for explicit scenario comparison, including visualizations of scenario differences. (C) 2001 Elsevier Science B.V. All rights reserved.