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2. We still allowed users to scroll since a user might actually want to quickly take a peek at the other pieces of data during a race (if their coach tells them that they need to keep an eye on thatnew types of data). This improves error correction if they accidentally misplace the data row but don't want to restart the race to rearrange it.
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2. If there exists no data for the stroke rate/split we grayed out the "Plot" button and replaced the numbers with "- " or "-- : --"Â respectively. Users found this to be very intuitive and never confused that feedback with lost data (usually it meant their accelerometer or GPS are were turned off).
"View Map" Pressed from previous (View Past Race) Screen -> View Map Screen
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1. Our controls overview had several iterations, but we are very happy with how it turned out. The hide/show button was initially placed on the top navigation bar, which was inefficient and not intuitive. After our first computer prototypeheuristic testing, we modified it and users found this new version much easier to use.
2. We decided to make the UI for using the playback screen exactly the same as the pre-race screen, so that users found it natural to drag rows and scroll around. The controls overlay didn't confuse anyone since it is clearly an overlay (the transparency give it the appearance of a window placed over the original view).
3. Our controls interface is very similar to the iPod controls, which improved learnability. Unfortunately, some users were confused at first by the slider; some thought it was for volume instead of a time-controller. Once they tried it once, they realized what it was and thought that the scrubbing was very intuitive and natural. This problem is discussed more in the Evaluation section below.
4. As the race plays back, each piece of data is added displayed exactly as it would be if you were recording the race again (the map updates, new strokes are logged, etc). This allowed users to playback a race and view the race it again as an observer instead of a participant.
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