1 i247: Information Visualization and Presentation Marti Hearst April 16, 2008

2 Today 3D visualization –3D in scientific visualization –Applying 3D to abstract data The PARC Information Visualizer and follow-ons 3D for data graphics –Navigating in 3D space –The debate: does 3D help? Cognitive abilities and 3D 3D vs 2D –Case Study: Helping Helicopter Pilots (scientific viz)

3 3D and Scientific Visualization Visualizing information that is inherently 3D is a special case of infoviz –“Easier” in the sense that the 3D inherently makes sense –Still, you need to choose what to show and what not to show. Images from

4 Chimera (from UCSF)

5 3D for Abstract Information Pioneering Work by Card and Robertson –Had state-of-the-art graphics hardware; wanted to see what happens when pushing the boundaries –Motivated by Card & Moran’s theories of cognitive architecture Information Visualizer (PARC) WebBook/Webforager (PARC, 1996) Data Mountain (MS Research, 1998) Task Gallery (MS Research, 2000)

6 Objective: –Decrease the costs for performing information- intensive tasks, or, alternatively, increase the scope of information that can be utilized for the same cost. Method: –Large Workspaces –Make the immediate workspace virtually larger –Real-Time Interaction –Maximize the interaction rates –Visual Abstractions – Speed assimilation and pattern detection 8 Information Workspaces

7 Information Visualizer research.microsoft.com/~ggr/gi97.ppt 17

8 Web Forager 24

Task Gallery (Robertson et al. 2000)

10 Data Mountain Robertson, Czerwinski et al, 1998 Follow-on to Information Visualizer Organizing bookmarks using pile metaphor Uses: –Spatial organization –3D view with 2D interaction –Cartoon animation details –Subtle audio cues Debate: –Is this better than 2D?

11 3D vs. 2D Cockburn & McKenzie ’02 –Results for prior work with 3D systems are primarily negative for viz of things that are not inherently in 3D, but really results are mixed –Compared 2D, 2½D and 3D views of web page thumbnails –Did this for both physical and virtual interfaces –Compared sparse, medium, and dense displays

12 3D vs. 2D: Cockburn & McKenzie ’02

13 3D vs. 2D Cockburn & McKenzie ’02 –Results: Time taken sig. increased through 2D -> 3D interfaces Subjective assessment sig. decreased 2D -> 3D Performance degraded with denser problems 3D virtual interface produced the slowest times People prefered the physical interfaces People were better at using their spatial memory than they expected to be There was a problem with the physical 2½D display

14 The Role of Cognitive Abilities Leitheiser & Munro ‘95 –Summarizes the results of earlier psychological research on spatial aptitiude –Also summarizes work on effects of spatial aptitude and UI use –Presents a study comparing a GUI with a command line interface, taking spatial abilities into account

15 The Role of Cognitive Abilities Leitheiser & Munro ’95 Hypotheses: –Users with high spatial ability would benefit more from the GUI than those with low spatial ability (H1) –Users with high verbal ability would perform better on command line interfaces (H2) Tasks: –Obtain system time, list files, look up a file update time, open a subdirectory, move a file, copy a file, etc –Between subjects GUI (Mac) vs. Command line (DOS) Findings: –H1 supported –H2 not supported –Everyone did better on the GUI Low spatial ability users using the GUI required 90% of the time needed for command line interface

16 Gender differences and 3D Previous studies often found gender differences in 3D navigation Czerwinski et al. wondered why; saw a hint in one study, did a followup study in detail Idea: change the assumptions –Make screen wider –Gender performance differences disappear –Both improved

17 3D and Data Graphics There have been lots of attempts to 3D-ify these Results seemed mixed Some modern versions of the ideas are here: – –

18 Interacting with 3D spaces Path-drawing for 3D walkthrough, –Igarashi et al, UIST ’98 Problem: interacting with 3D via 2D screens Solution: be clever about how to convert 2D to 3D based on what the user is likely to intend

19 Creating in 3D Spaces Teddy: A 3D Drawing System –Igarishi

20 Other 3D Creation Tools Lots of other great ideas from Igarashi’s lab: –

21 Slides from Heiser et al. Sequences of Steps vs 3D + Animation Heiser, Phan, Agrawala, Tversky, Hanrahan ‘04 Domain: assembly instructions Identify –How people conceive of 3D assemblies –How people comprehend visual instructions Validate –Build automated instruction design system –Evaluate usability of resulting instructions

22 Slides from Heiser et al. Ensure Visibility of Parts Show parts added in each step Show mode and location of attachment Avoid changing viewpoint Use physically stable orientation

23 Slides from Heiser et al. Structural diagrams Action diagrams Illustrate Assembly Operations Use action diagrams rather than structural Use arrows and guidelines to indicate attachment

24 Improving Aviation Safety with Visualization Cecilia Aragon, graduated from here Goal: reduce helicopter landing accidents caused by invisible air turbulence Approach: use a new technology called lidar and try to visualize its output Finding: it helped reduce simulated accidents (!) but only when the visualization was made as simple as possible.

25 Slide by Cecilia Aragon Motivation Invisible airflow hazards cause aircraft accidents –Wind shear –Microbursts –Vortices (turbulence) –Downdrafts –Hot exhaust plumes Crash of Delta Flight 191 at DFW 1985 (microburst) NTSB database –21,380 aircraft accidents –2,098 turbulence/wind related

26 Slide by Cecilia Aragon Preliminary Usability Study

27 Slide by Cecilia Aragon Preliminary usability study: goals Assess efficacy of presenting airflow data in flight Obtain expert feedback on presentation of sample hazard indicators to refine design choices

28 Slide by Cecilia Aragon Usability study: low-fidelity prototype Rhino3D (3D CAD modeling program) –Easy access to ship models, ease of rapid prototyping –Chosen over 2D paper prototype, MS Flight Simulator, WildTangent, VRML-based tools, Java and Flash Series of animations simulating helicopter’s final approach to landing Different types of hazard indicators Get pilot feedback and suggestions (interactive prototyping)

29 Slide by Cecilia Aragon Low-fi usability study screen shots

30 Slide by Cecilia Aragon Low-fi usability study screen shots

31 Slide by Cecilia Aragon Low-fi usability study participants Navy helicopter test pilot, 2000 hours of flight time, 17 years experience Navy helicopter flight test engineer, hours of simulator time, 100 hours of flight time, 17 years experience Civilian helicopter flight instructor, 1740 hours of flight time, 3 years experience

32 Slide by Cecilia Aragon Low-fi usability study results All participants said they would use system Feedback on hazard indicators: –Color: all preferred red/yellow only –Transparency: should be visible enough to get attention, but must be able to see visual cues behind it –Depth cueing: all preferred shadows below object, #1 said shadows alone sufficient. #2 wanted connecting line. No one wanted tick marks or numeric info. –Texture: #1, #2 didn’t want. #3 suggested striping –Shape: Rectilinear and cloud shapes favored. Keep it simple! Watch for conflicting HUD symbology.

33 Slide by Cecilia Aragon Flight Simulation Usability Study

34 Slide by Cecilia Aragon Flight Simulation Usability Study Implement visual hazard display system in simulator based on results from low-fidelity prototype Advanced Rotorcraft Technology, Inc. in Mountain View, CA, USA –High-fidelity helicopter flight simulator –Accurate aerodynamic models Use existing ship and helicopter models, flight test data Simulated hazardous conditions, create scenarios, validated by Navy pilots and flight engineers

35 Slide by Cecilia Aragon Flight Simulation Usability Study: Participants 16 helicopter pilots –from all 5 branches of the military (Army, Navy, Air Force, Coast Guard, Marines) –civilian test pilots (NASA) –wide range of experience 200 to 7,300 helicopter flight hours (median 2,250 hours) 2 to 46 years of experience (median 13 years) age 25 to 65 (median age 36) No previous experience with airflow hazard visualization

36 Slide by Cecilia Aragon Simulation Experiment Design 4 x 4 x 2 within-subjects design (each pilot flew the same approaches) 4 shipboard approach scenarios 4 landing difficulty levels (US Navy Pilot Rating Scale - PRS 1-4) Each scenario was flown at all difficulty levels both with and without hazard indicators Orders of flight were varied to control for learning effects

37 Slide by Cecilia Aragon Airflow Hazard Indicators in Simulator

38 Slide by Cecilia Aragon Hypotheses 1. Crash rate will be reduced by the presence of hazard indicator (LD 3). 2. Crashes will be eliminated by red hazard indicator if a standard operating procedure (SOP) is given to the pilots (LD 4). 3. Hazard indicator will not cause distraction or degradation in performance in situations where adequate performance is expected without indicator (LD 2). 4. Pilots will say they would use airflow hazard visualization system

39 Slide by Cecilia Aragon Hypothesis 1 confirmed Presence of the hazard indicator reduces the frequency of crashes during simulated shipboard helicopter landings (t-test for paired samples, t=2.39, df=63, p= ). 19% -- > 6.3%

40 Slide by Cecilia Aragon Hypothesis 2 confirmed Presence of the red hazard indicator combined with appropriate instructions to the pilot prevents crashes (t=4.39, df=63, p 0%

41 Slide by Cecilia Aragon Hypothesis 3 No negative effect of hazard indicator. 8%-- > 8%

42 Slide by Cecilia Aragon Hypothesis 3 (cont’d) Pilots believe hazard indicators were not distracting (Probe 6 results).

43 Slide by Cecilia Aragon Hypothesis 4 confirmed Pilots would use the system (Probe 21 results).

44 Slide by Cecilia Aragon Analysis by Pilot Experience Level Same general trends -- but small sample size No significant difference between the groups

45 Slide by Cecilia Aragon Analysis of Subjective Data 94% found hazard indicators helpful

46 Slide by Cecilia Aragon Analysis of Subjective Data Is motion (animation) helpful or distracting?

47 Slide by Cecilia Aragon Conclusions Flight-deck visualization of airflow hazards yields a significant improvement in pilot ability to land safely under turbulent conditions in simulator Type of visualization to improve operational safety much simpler than that required for analysis Success of user-centered design procedure