Automating the Design of Graphical Presentations of Relational Information

1. Automating the Design of Graphical Presentations of Relational Information Jock MacKinlay Beth Weinstein March 14, 2001

2. Paper Outline • Introduction • Expressiveness • Effectiveness • Composition • Implementation

3. Previously application designers had to anticipate every situation and “predesign” graphic designs In related work, the BHARAT system, automatically creates 2D graphical designs based on the data type. For example, the system automatically chose to show the data as a line chart if the data was continuous. Introduction

4. Introduction • MacKinlay’s goal was to build a presentation tool (APT) that would create a graphic design that would express relations and their basic properties effectively • APT would have the best way to view 2-D data using expressiveness and effectiveness criteria. The paper focuses on 2-D static presentations of relational data (scatter plots, bar charts, etc.)

5. Introduction • Three types of data • ordinal (Monday, Tuesday, Wednesday) • nominal (United States, Mexico, Canada) • quantitative (1, 2, 3) • Problems could arise when there are multiple and conflicting criteria for a data set

6. Expressiveness Criteria identify graphical languages that express the desired information • Expressive if • include all data in the set • include only data from the set

7. Expressiveness Criteria

8. Effectiveness Criteria identify which graphical languages is most effective at using the output and human capabilities • Based on human perceptual capabilities • Graphical design interpreted quickly and accurately • Cleveland and McGill’s conjectural theory - different graphical designs are interpreted by people with varying accuracy

9. Expressiveness Criteria

10. Effectiveness Criteria

11. Composition • Merge different encoding techniques not usually combined

12. Implementation • Partitioning • A divide and conquer algorithm • Partition on most important element • Selection • For each partition, a list of graphic design is generated based on expressiveness criteria • Then, the list is ordered by the effectiveness criteria • Composition • Each partition’s graphic design is tested to see if they both can be applied, if not the next most effective graphic design is used

13. Favorite Sentence “…an important responsibility of a user interface is to make intelligent use of human visual abilities and output media whenever it presents information to the user.”

14. Reference Notes • MacKinlay - Ph.D. dissertation • Cleveland and McGill • General, well-cited references • Tufte • Knuth

15. Critique • Strengths • Proves that a graphical design may not be appropriate for all types of data • Gives a criteria for perceptual tasks • Weaknesses • Vague on how extended Cleveland and McGill’s criteria • Composition algebra unnecessary

16. Contributions • Provides a ranking of perceptual tasks for nominal, ordinal, and quantitative data • Contributes a new graphical designs by combining perceptual tasks • Creates a tool that will create expressive and effective graphical designs based on the data