preadsheets have proven highly successful for interacting with numerical data, such as applying algebraic operations, defining data propagation relationships, manipulating rows or columns, and exploring "what-if" scenarios. Spreadsheet techniques have recently been extended from numeric domains to other domains. 1,2 Here we present a spreadsheet approach to displaying and exploring information visualizations, with large, abstract, multidimensional data sets that are visually represented in multiple ways. We illustrate how spreadsheet techniques provide a structured, intuitive, and powerful interface for investigating information visualizations. An earlier version of this article appeared in the proceedings of the 1997 Information Visualization Symposium. 3 Here we refocus the discussion to illustrate principles that make the spreadsheet approach powerful. These principles show how we can perform many user tasks easily in the visualization spreadsheet that prove much more difficult using other approaches. The visualization spreadsheet's benefit comes from enabling users to build multiple visual representations of several data sets, perform operations on these visualizations together or separately, and compare and contrast them visually. These operations are becoming ever more important as we realize certain interaction capabilities are critical, such as exploring different views of the data interactively, applying operations like rotation or data filtering to a group of views, and comparing two or more related data sets. These operations fit naturally into a spreadsheet environment. These benefits derive from the way spreadsheets span a range of user interactions. On the one hand, spreadsheets directly benefit end users, because the direct manipulation interface makes it easy to view, navigate, and interact with the data. On the other hand, spreadsheets provide a flexible and easy-to-learn environment for user programming. The success of spreadsheet-based structured interaction eliminates many of the stumbling blocks in traditional programming environments. Spreadsheet developers create templates that enable end users to reliably repeat often-needed computations without the effort of redevelopment or coding. Users do not have to worry about the data dependencies between data sets or memory management. These programming idiosyncrasies are taken care of automatically. By providing a natural environment to explore and apply operations on data, visualization spreadsheets easily enable the exploration of data sets. Based on our experiences and drawing on others' past work, 1-3 we define the spreadsheet paradigm's characteristics as follows: s The tabular layout lets users view collections of visualizations simultaneously. Cells can handle large data sets instead of a few numbers. s Operators are available for generating or modifying cell contents. The visualization spreadsheet includes a rich variety of operators for different types of data sets. Operators can be applied across a specified range of operand cells, such as a whole column. s The spreadsheet keeps track of the dependencies between cells and automatically updates the cells appropriately when they are manipulated. These characteristics give the spreadsheet paradigm its fundamental advantages. We borrow these charac-
Chi REF applies the spreadsheet paradigm to information visualization in his Spreadsheet for Information Visualization (SIV).
Principles for Information Visualization Spreadsheets
IEEE Computer Graphics and Applications
IEEE Computer Graphics and Applications
Computer Science