Paper Reading #22: Mid-air pan-and-zoom on wall-sized displays

References
Mid-air pan-and-zoom on wall-sized displays by Mathieu Nancel, Julie Wagner, Emmanuel Pietriga, Olivier Chapuis, Wendy Mackay.  Published in the CHI '11 Proceedings of the 2011 annual conference on Human factors in computing systems.


Author Bios

• Mathieu Nancel is currently a PhD student in HCI in the Université Paris-Sud XI under the supervision of Michel Beaudouin-Lafon and Emmanuel Pietriga.
• Julie Wagner is a PhD student in the insitu lab in Paris, working on new tangible interfaces and new interaction paradigms at large public displays.
• Emmanuel Pietriga is currently a full-time research scientist working for INRIA Saclay - Île-de-France.  He is also the interim leader of INRIA team In Situ.
• Olivier Chapuis is a Research Scientist at LRI.  He is also a member of and team co-head of the InSitu research team.  
• Wendy Mackay is a Research Director with INRIA Saclay in France,  though currently on sabbatical at Stanford University. She is in charge of the research group, InSitu. 

Summary 

• Hypothesis
• The main hypothesis of the paper is that there is a need for more research on complex tasks when dealing with high resolution wall-sized displays.  The authors made seven smaller hypotheses about how people best interact with tools.
1. Two hands are faster than one
2. Two-handed gestures should be more accurate and easier to use.
3.  Linear gestures should map better to the zooming component, but should eventually be slower because of clutching.
4. Users will prefer clutch-free circular gestures.
5. Techniques using fingers should be faster than those requiring larger muscle groups.
6. 1D path gestures should be faster, with fewer overshoots than techniques with lesser haptic feedback.
7. 3D gestures will be more tiring.
• Methods
• They conducted an experiment with 12 participants based on three primary factors: handedness, gesture, and guidance.  They controlled for potential distance effects by introducing the Distance between two consecutive targets as a secondary factor. The pan-zoom task involved navigating through two groups of concentric circles, starting at a high zoom level and zooming out until the neighboring group is visible.  Then they pan and zoom until they reach the target group.
• Results
• The data from the pan-zoom task strongly supported the first hypothesis, as well as numbers 5 and 6.  They were surprised to find that their third hypothesis was not supported; linear gestures are faster than circular ones.  Finally, as they expected, participants found that hypothesis 7 held true, and that IDPath guidance was least tiring but 3DFree was most tiring.
• Contents
• The paper discusses how users might best interact with a large screen by studying several different motions and commands.  They wanted to observe ease of use, causes of fatigue, and how simple or complex the interactions might be.  They proposed several ideas at the beginning to guide their research, and then performed an experiment to highlight the key points.  They found that while most of their hypotheses were supported, they had judged one or two points inaccurately.

Discussion
    I think this was a very well put together paper.  I feel that the authors did a good job defining their parameters and goals, and then delivering the results thoroughly.  I think it would have been interesting if they had done a little bit more experimentation, maybe trying a few different approaches to get the information they were looking for.  However, overall I was impressed by the research and findings.