Monday, August 3, 2015


The "Points-to-Set" graph was inspired by the work of Francis X. DieboldGlenn Rudebusch and Professor Diebold's students at the University of Pennsylvania.  In December, 2014, Professor Diebold published "A Tennis Match Graphic" on his blog No Hesitations, and in February when I was just discovering D3 I decided to attempt to recreate his work for the data I had just learned to parse from ProTracker Tennis.  Here is the result of that effort, taken from the 2015 Wimbledon semifinal match between Roger Federer and Andy Murray, where you can view these charts "live":

And here is the latest version:

We can think of the "Points-to-Set" number as the minimum distance from the current number of points won until the end of the Set; it always assumes your opponent wins no additional points.  In TAVA this number is expressed graphically for each player to indicate at any given moment in a Set which player is closer to winning.

To win a standard Set in a tennis match a player must, at a minimum, win six games and be ahead by two games.  Giving no more than two points away, there is a minimum of four points which must be won in each game.  That means that at the beginning of a Set each player needs twenty-four points to win the Set.  The Y-axis of the graph below ranges from 24 up to 0, which is where the Set concludes. The X-axis shows the total number of points within the Set.  In the match depicted in these "Points-to-Set" visualizations you can see the varying number of points which had to be played for Roger Federer to close out each Set.

Every point won brings a player closer to the end of the Set, obviously.  Some games, when they are lost, increase the "Points-to-Set" number.  For instance, at the beginning of a Game when the score is 5-4 in the Set, the first player needs only four points to win, while the second requires twelve.  If the first player loses the game and the score becomes tied at 5-5, each player is then eight points from winning the Set. In fact this scenario occurred twice in this match, in both the first and second Sets which were won by Federer 7-5.  You may also notice that in the first game of both the second and third Sets there was a moment when Andy Murray needed 25 points to win the Set.  This actually occurs quite frequently when the first few games are won by one player.  When a player leads 5-0, the opponent actually needs 28 points to win the set.

In the second Set the game which Federer lost there were seven deuces; you can see this in the "Points-to-Set" graphic below where the lines for both players become jagged. You can also see that Federer failed to convert on six breakpoints before winning the set by finally converting a breakpoint.

As I work on the re-write of TAVA I'm developing a gallery of re-usable visualization components and adding configurable features.  In addition to the "orientation highlighting" demonstrated above, I'm adding "game highlighting", which you can see in the chart for the third set below:

When using the "Points-to-Set" component in TAVA, the corresponding moments of the match are highlighted on the Sunburst and you can see the longest game of the match occurred in the second set and was won by Andy Murray (purple) when Federer failed to convert two breakpoints.

In a recent postProfessor Diebold has updated his Tennis Graphic to include elements which indicate where breakpoints occurred and highlight when tiebreaks take place.  Here is the site where his team has collected the visualizations they've created.  I've taken some of these ideas on board and in the re-write of TAVA I'm going to try to push the features and usefulness of the "Points-to-Set" graphic further.  I am intrigued by the idea of producing some variation of a Points-to-Match graphic as a slider/filter for generating dynamic statistics for a range of points within a match...

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