Thursday, July 30, 2015

Sunburst: Match at a Glance

The goal of the Sunburst Visualization is to provide an information-rich view of a match in a single graphic. The layout for the Sunburst is like a clock.  The match begins at 12:00 and proceeds clockwise.  

The Sets, Games and Points won by each player are colored: Djokovic is blue, Nishikori is purple. The circle at the center of the visualization indicates the outcome of the match.  In this case it is blue, indicating that Djokovic won the match. 

The first ring around the center represents Sets. Djokovic won the first Set, Nishikori the second Set, and Djokovic the third Set. The length of each ring segment indicates the length of each Set relative to every other Set. The second ring from the center represents Games. The darker the color, the more intense the game (in terms of length of rallies). The third ring from the center represents Points. The darker the color, the longer the rally for the point. 

The final and outermost ring represents significant Shots: First and Second Serves, Return of Serve, and the final, Key Shot.  Shots colored Green are Winners.  Light green represents a Shot which forced the opponent to make an error ("forcing shots").  Red represents Errors.  Shots that are "In" are colored to indicate who made the Shot.

Comparing Sunburst visualizations of different matches you can quickly get a gut feel for whether one or both players achieved a significant Aggressive Margin (see also here).  

At the moment I spend most of my time tracking U12 and U10 matches, so the outer ring is mostly Red and the Aggressive Margins are usually negative. Compare the Djokovic/Nishikori match on the left to the Semifinals match between Roger Federer and Andy Murray at Wimbledon (2015):

In the match between Djokovic and Nishikori the relative Aggressive Margins were 5% and -9% whereas in the Federer/Murray match the relative Aggressive Margins were 29% and 23%.


[UPDATE: The role of the Sunburst Visualization has been diminished in the latest update to TAVA.  It is still used for orientation highlighting and some navigation.  Sunburst will make a more forceful return at a later date when new functionality is added.]

The Tennis AiP visualization application (TAVA) uses the Sunburst as a control structure to aid in the exploration of various aspects of a match. Clicking on a Set segment reveals a Points-to-Set visualization; clicking a Game segment reveals a GameFish visualization; clicking a Point reveals the GameFish where that point occurred.

The Sunburst Visualization is zoomable.  Double clicking a Set segment transitions to a view of a single Set, while double clicking a Game segment transitions to a view of a single Game:

In TAVA, clicking the center of the Sunburst initiates a zoom transition to the enclosing Set or to the initial Match view.  From the initial Match view, clicking the center of the Sunburst transitions the display to a Momentum Chart.

The Sunburst also provides "Orientation Highlighting" while using other components of TAVA to indicate where Shots and Points occurred:

Finally, TAVA uses the Sunburst to indicate where Breakpoints occurred during a match:

In the visualization above Djokovic (Blue) had a breakpoint opportunity in the second game; he successfully converted (Green).  In the sixth game Djokovic had three breakpoints, but Nishikori saved the breakpoints and Djokovic failed to convert (Red).  In the final Game of the first Set, Nishikori (purple) had two breakpoints which he failed to convert (Red).

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