Visualization: Vertical spray chart

I love spray charts.

They’ve been around forever, but for my money, they still convey a larger amount of information in a concise and readable manner than nearly any other form of baseball chart. One look, and it’s immediately obvious that Jason Giambi is a dead pull hitter. Or that Adam Dunn has power anywhere on the field. Spray charts make sense of huge amounts of tabular batted ball data, where patterns and relationships are nearly incomprehensible at first glance.

But while spray charts show the difference between a hitter that likes to go to left or right field, they don’t usually show the difference between batters who tend to hit balls in the air and batters who slap them on the ground. So why not turn the spray chart on its side?

image

Click to enlarge.

Now, basically the only way to get real elevation angle data is to tap in to the incredible resource that is HITf/x. Unfortunately, while MLBAM and Sportvision make PITCHf/x data freely available for use, HITf/x data isn’t public. So that’s out. To get the angle data for this chart, I had to use an elevation angle proxy. Every vector on the chart corresponds to one of the top 20 batters in offensive production, as of this Monday. A vector would be completely horizontal if the batter only hit ground balls, while a vertical vector would mean that the batter hit only fly balls. A batter who hit an equal amount of ground balls and fly balls would have a vector pointing 45° above the horizontal, with all other angles corresponding to different ground ball/fly ball ratios accordingly. The length of each vector is mapped to slugging percentage, to get sort of a proxy for power.

As you’d expect from a huge home run hitter, Adam Dunn has the steepest angle by far, at 64° above the horizontal. He’s consistently among the league leaders in fly balls, and this year is no exception. On the other hand, Melky Cabrera is usually fairly average with his batted ball distribution, but this year he’s hitting nearly 60 percent of his batted balls on the ground. Whatever he’s doing, it seems to be working for him.

If there’s enough interest, I can extend this idea to pitchers, and I can also update the chart every once in a while with new batted ball data.

References & Resources

  • To be more precise, the angle is calculated from the arctangent of the FB/GB ratio. Then, with the angle and the radial component (slugging percentage), it’s a matter of converting polar coordinates to rectangular ones.

  • The league average elevation angle lies between Adam Jones and Andrew McCutchen‘s vectors, at 37° above the horizontal.
  • The top 20 batters were sorted by Fangraphs’ Batting Runs metric.
  • Have I mentioned that Josh Hamilton is an absolute monster? Because he is.
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Comments

  1. Jim said...

    This is a really nice chart, the pitchers’ version would also be interesting.

    The scale of the angle threw me off at first – I thought the spray angle was going to be literally average elevation off the bat or something like that. I wonder if it would be possible to create a heat map of a single batter’s “true” vertical spray?

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