DESCRIPCION BIOCULTURAL

We evaluated the quantitative data obtained from the log les of the iPad application and also qualitative data obtained from questionnaires given to the test subject as well as comments the test subjects made during the experiment.

3.2.5.1 Quantitative Results

The average task execution times for both the experiment and the warmup exercise are shown in Figure 3.10. On average, TOUCH and SAZ performed better than FLICK or FLICK-SAZ. Due to the low num- ber of users, however, generalizations are difficult. For instance, FLICK was the fastest technique for two of the test subjects. In general, the task execution times varied more for the ick techniques, lying be- tween 3.2-4.96 minutes for FLICK and 2.86-4.94 minutes for FLICK- SAZ compared to 1.65-2.23 minutes for TOUCH and 2.87-3.61 min- utes SAZ. Regarding the two FLICK techniques, FLICK-SAZ was the faster technique for 3 participants.

In the warmup exercise, TOUCH had the lowest average task comple- tion time. FLICK-SAZ performed better than FLICK or SAZ, which can be explained by the higher learning curve inherent to SAZ (Section 3.1.6).

When looking at the number of screen touches counted during the FLICK and FLICK-SAZ lead to a reduction in screen touches compared to TOUCH experiment, we can observe that FLICK and FLICK-SAZ do reduce the

number of average screen touches from 121 for TOUCH to 78 and 74, for FLICK and FLICK-SAZ, respectively (Figure 3.11). This amounts to a reduction of almost 40%. Because SAZ is mainly tilt-based, it we only counted an average of 11 touches for that technique.

60 3 Continuous Interaction and State-Space Systems

TOUCH SAZ FLICK-SAZ FLICK 0 1 2 3 4 5

Average Task Completion Time (min)

1.93 3.14 3.88 3.97 1.50 2.00 1.99 2.35 Study Warmup

Figure 3.10: The average task completion times in minutes for each input technique during the experiment and during the warmup exer- cise.

TOUCH SAZ FLICK FLICKSAZ

0 20 40 60 80 100 120 140 Number of Touches µ=121 µ=11 µ=78 µ=74

Figure 3.11: The number of touch events measured for each input technique. The diamonds represent the average number of touches over all participants for the respective input technique.

3.2.5.2 Qualitative Results

Figure 3.12 shows the average ratings and rankings for the USE ques- tionnaire. TOUCH was rated and ranked best, followed by SAZ and the ick-based techniques for Satisfaction, Usability and Learnability. How- ever, FLICK and FLICK-SAZ were rated better forUsefulnessthan SAZ. This may be due to tilt-based techniques being less familiar to users than ones based on touch.

3.2 Flick-and-Zoom: Touch-Based Automatic Zooming for Mobile Map Navigation 61

TOUCH SAZ FLICK FLICK-SAZ

0 1 2 3 4 5 6

Average Rating

TOUCH SAZ FLICK FLICK-SAZ

0 1 2 3 4

Average Rank

Figure 3.12: Left: the average USE Questionnaire ratings by input technique. Right: the average USE Questionnaire rank by input technique. Error bars are omitted due to the low number of study participants (N=4).

3.2.6

User Feedback

During the user study, the test subjects were encouraged to express their thoughts, impressions and actions orally. In the following, we summarize the most common items of spoken user feedback:

• All users preferred TOUCH as this is the technique that they were the most familiar with, since this technique is standard on most multi-touch mobiles. Because of their knowledge of how the in- terface would react, the users felt that they had more control over the map and that they were more effective. However, the users did criticize the large number of inputs required to reach each tar- get. Also, several users mentioned that repeated pinch-to-zoom input was “annoying and slow”.

• Most users mentioned that the tilt-based navigation using SAZ was easy to learn and fun. Due to the direct translation of the tilt movement to scroll direction and zoom level, this technique was easy to grasp for most users. By contrast, the users found that the zoom-out and zoom-in speeds were too fast. Although the users mostly liked SAZ during the warmup exercise, some users got annoyed during the main task and found that “ying on the map” was fun but not a real alternative to a standard user interface, since it wouldn’t be appropriate in certain everyday situations, i.e. in business settings.

• FLICK and FLICK-SAZ obtained positive mentions for providing a good overview of the map when only the coarse direction of the target is known. The advantage versus TOUCH is that the map

62 3 Continuous Interaction and State-Space Systems

keeps moving once scrolling has been initiated, and that the map can be seen scrolling without occlusion from the user’s hand. Ad- ditionally, all test subjects liked the possibility to stop scrolling and zoom in fully using a single touch on the map’s surface. How- ever, the users would also have liked the ability to stop scrolling while maintaining the current zoom level, which could be easily incorporated into the existing application.

• Initially, all users did not feel that FLICK-SAZ was intuitive. With time, however, all subjects developed skills to interact using this method and mentioned that the slider would allow them to get an overview of the map position and the scrolling direction. The standard interaction sequence that evolved led to the users per- forming a fast ick in the desired direction and then controlling the slider to select the preferred zoom level. The scroll direction was then corrected by inputing additional icks. The ability to “skip” to the target location directly by tapping on it was used often. The ability to manually override the automatic zooming using the slider was mentioned favorably.