IS482/682: Information Visualization

1. IS482/682: Information Visualization • What to “know”? • Goals of information visualization. • About human perceptual capabilities. • About the issues involved in designing visualization for multiple dimensions and the heuristics for best practices in visualization design. • What to be able to “do”? • Choose and design an effective information visualization for a small data set. • Design a dashboard for a small data set. • Evaluate whether a design is effective or not.

2. Intelligence in Business Intelligence... In “business intelligence,” what do we mean by “intelligence”? Where does “intelligence” come from? How is “intelligence” produced?

3. Goal of information visualization:Use human perceptual capabilitiesto gain insightsintolarge data sets.

4. Overall View of BI Information Visualization Clean data Complete data Longitudinal data Consistent data More data Accurate calculations Flexible design Properties Patterns Relationships Comparisons Anomalies Trends Enhanced understanding Improved decision making Amplify cognition

5. How does information visualization enhance understanding & amplify cognition? • Increase available brain resources • Enhance parallel perceptual processing • Offload work from cognitive to perceptual system • Reduce search time • Enhance recognition of patterns • Encourage recognition instead of recall • Enhance “chunking” into appropriate memory sizes for both processing and recall • Provide focus/emphasis • Highlight images with “pop-out” effect

6. Two general stages of visual processing • Rapid parallel processing • Feature Extraction: edges, orientation, color, texture, motion • Relies on commonly accepted images (cultural, personal) • Transitory: Uses primarily short-term memory, but can leave impact • Serial goal-directed processing • Object Recognition: visual attention & memory important. • Uses both short-term memory and long-term memory • More emphasis on arbitrary aspects of symbols • Different pathways for object recognition & visually guided motion

7. Pre-attentive processing • Visual properties processed without significant cognition. • No need to focus attention; must stand out • Can be perceived immediately; less than 250 ms • May mislead viewer; may create inappropriate and lasting significant emphasis • The visual properties are: • Color • Motion • Edge segmentation; primitive features • Orientation • Size

8. Expression recognition

9. Parallel Processing • Orientation • Texture • Color • Motion • Size • Detection • Edges • Regions • Light • 2D Patterns • Serial Processing • Object Identification • Collation • Short Term Memory 5 ± 2 = 3 to 7 Objects

10. Brief recap of class… • The goal of information visualization is to enhance understanding and amplify cognition. • Increase available brain resources • Reduce search time • Enhance recognition of patterns • Provide focus/emphasis • Make best use of parallel and serial processing. • Understand how people process images. • Understand the speed with which people process images without conscious thought.

11. Design and art are different Artis valued for its originality and expressiveness. Artis valued for pushing the bounds of accepted norms and potentially expanding the definition of those norms. Design is valued for its fitness to a particular user or task. Design is valued for its effectiveness and use.

12. Affordance • “An affordance is a quality of an object which allows an individual to perform an action.” (Wikipedia) • A knob implies twisting, a string means pulling. • In design, we look at how the affordances of an object reveal how it will be used. • A push plate on a door means that it should be pushed, rather than pulled, open. • A line showing where the average is on a graph means that the viewer should compare the data to the average. • A vertical line means someone should read a table or graph vertically. • Design is “good”when the perceived affordance (“is for”) is equivalent to the actual affordance.

13. Focus on the... Task rather than the visualization User rather than the technology Information content rather than the data Message rather than the medium Accuracy rather than beauty

14. Primary visualization tasks for BI • Analyzing • Discover the message in the data. • Monitoring • Track information and look for anomalies. • Planning • Prepare for the future. • Communicating • Send a message to another person.

15. Think about... • The differences. Like: • The difference between analyzing and communicating. • The difference between monitoring and analyzing. • The difference between planning and monitoring. • Think what about the differences? • Who does it? • Why is the person doing it? • How does it happen? • What are the results?

16. What visualization should do (Tufte 1983) Show the data Induce to viewer to thinkabout the data Avoid distorting what the data have to say (next 3 slides) Present many numbers in a small space Encourage the eye to comparedifferent pieces of data Reveal the data at several levels of detail, from overview to fine structure Make large data sets coherent Serve a clear purpose Be closely integrated with the statistical and verbal descriptions of a data set.

17. Sample information visualizations http://www.gapminder.org/ http://visual.ly/ http://www.coolinfographics.com/ http://www.babynamewizard.com/voyager http://www-958.ibm.com/software/data/cognos/manyeyes/

18. Heuristics galore!! Tufte’s principles (short and sweet) Nielsen’s ten usability heuristics (long and detailed)

19. Tufte’s principles • Provide the greatest number of ideas in the shortest time with the least ink in the smallest space • Enforce visual comparisons • Show comparisons adjacent in space • Show causality • Show multivariate data • Use direct labeling: Avoid separate legends and keys • Use small multiples (called trellis chart): a number of small, simple adjacent charts to encourage comparison • Avoid “chart junk”

20. Nielsen’s ten usability heuristics • Visibility of System Status • Always keep users informed about what is going on. • Provide appropriate feedback within reasonable time. • System MatchesReal World • Speak the users' language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. • Follow real-world conventions, making information appear in a natural and logical order. • User Control and Freedom • Users often choose system functions by mistake. • Provide a clearly marked "out" to leave an unwanted state without having to go through an extended dialogue. • Support undo and redo.

21. Nielsen (cont.) • Consistency and Standards • Users should not have to wonder whether different words, situations, or actions mean the same thing. • Follow platform conventions. • Error Prevention • Even better than good error messages is a careful design which prevents a problem from occurring in the first place. • Recognition rather than Recall • Make objects, actions, and options visible. • User should not have to remember information from one part of the dialogue to another. • Instructions for use of the system should be visible or easily retrievable whenever appropriate.

22. Nielsen (getting closer...) • Flexibility and Efficiency of Use • Accelerators -- unseen by the novice user -- may often speed up the interaction for the expert user so that the system can cater to both inexperienced and experienced users. • Allow users to tailor frequent actions. • Aesthetic and Minimalist Design • Dialogues should not contain information which is irrelevant or rarely needed. • Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility. • Help users Recognize, Diagnose, and Recover from Errors • Expressed in plain language (no codes) • Precisely indicate the problem • Constructively suggest a solution.

23. Nielsen (the last!) • Help and Documentation • Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. • Help information should be easy to search, focused on user's task, list concrete steps to be carried out, and not be too large.

24. The purpose of the chart is to compare the sales in Company G to the rest of the companies. Does it do a good job?

25. Better in 3D?

26. The purpose is to track quarter-to-date performance of sales representatives for a sales manager, including relative performance. Does it work?

27. The purpose is to compare one product’s sales to other products. Good or bad visualization?

28. The purpose is to display sales revenue in the state of Kansas associated with 12 products across the four quarters of a year. How would you improve this visualization?