There are 30 stadiums across Major League Baseball. No two of them are the same.

Pro ballparks come in all shapes and sizes, sometimes due to the shape of the city block on which they were built, sometimes based on a team’s strengths (or weaknesses), and sometimes just to add character. Because their shapes differ, a home run hit in one park might not be a home run in another. For instance, a ball over the left field fence in Seattle might hit the Green Monster at Fenway, or a homer to deep center field at Dodger Stadium might not leave the park at Coors Field.

That’s what inspired us to create the No Doubter report. We define a “no doubt” home run as one that is hit hard enough, long enough, and high enough to leave any major league field. This season, there’s been home runs. Only of them were no doubters.

In this piece, the second in a series on the irregular outfields of baseball, we look at every home run hit this season to determine which can be called No Doubters. And in the process, we’ve crowned the top home run hitter of 2019.

2019 No Doubt Leaders

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Click a player to see his 2019 homeruns. See the full leaderboard

No Doubters

No Doubt Rate

We used Statcast data, courtesy of MLB’s Baseball Savant, to get the trajectory for every home run hit in a season that was defined by them. We combine that with outfield measurements and fence heights for every park to calculate if each HR was a no doubter or not.

As of September 30th, Mike Trout is this year’s leader in no doubters with 16, just ahead of Jorge Soler. The Nationals’ Trea Turner, meanwhile, leads the league in no doubt rate. He may have hit only 19 home runs this season, but 10 of those would have left any MLB stadium.

The visualization below shows whether each of the season’s home runs was hit deep enough to clear the fence at a given major league ballpark.

Was That Home Run a No Doubter?

Click a homerun to see how it fared across MLB parks.Hover over a field outline to see the park name and if the ball didn’t make it out.
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No Doubter?

So who do we crown this season’s true home run king? Even though Pete Alonso set a rookie record on his way to a league-leading 53 home runs, less than 20% of them were no doubters. By contrast, Trout’s no doubt rate topped 35% for 2019.

Check out the full leaderboard below to explore the leaders, search for your favorite player, or sort by no doubt rate, exit velocity, or distance.

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Search for a player below, sort by a stat, or click a player to see his 2019 homeruns.
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No Doubt Rate

Methodology

The Project

This project was created by Sam Vickars (copy, design, code) and Michael Hester (code, data) of The DataFace. Statcast data is from MLB’s Baseball Savant and is updated on this page regularly.

Field outlines are traced from a combination of Google Earth, aerial imagery, and official MLB field diagrams, using the diamond as a consistent scale. Wall heights are based on stadium photographs, official MLB dimensions, and Andrew Clem’s Clem’s Baseball.

We used d3 as a basis for the whole project, and specifically d3.path() to move from Illustrator to d3 SVG, as well as some very complicated math done in javascript.

The Math

To determine if a specific home run was a no doubter, we first had to determine its trajectory. We did this with six columns of Statcast data: hit_distance (projected distance), launch_angle, launch_speed (exit velocity), plate_z (height of ball at home plate), hc_x (x coordinate of batted ball), and hc_y (y coordinate of batted ball).

While Statcast’s hit distance could tell us whether a ball was hit far enough to reach the wall in another stadium, we still needed to know whether the ball would have been high enough to clear the fence. So we first calculated the batted ball’s total time in air (tT = -Vyi ∓ √(Vyi2 + 2ghi) / g), the ball’s X acceleration (ax = (-2Vix / tT) + (2dh/tT2)), and the time it would take the ball to reach the wall (tw = (-Vxi ∓ √Vxi2 + 2axdw) / ax). Then we plugged those values into this equation to determine the ball’s height at the wall: y = (Vyitw) + ½gtw2. If the ball’s height would have been greater than the fence’s height when it reached the fence in all 30 stadiums, it was considered a no doubter.

We also considered accounting for slight differences in air quality and the strength of gravity across the parks. In theory, the gravitational pull on the ball at a high-altitude park like Coors Field in Denver, Colorado will be slightly lower than at a park nearer to sea level. That would mean the value for negative vertical acceleration in the calculations above would be less, allowing the ball to carry just a little farther. After doing the math though, we found this difference to be negligible.