PITCHf/x is a pitch tracking system, created by Sportvision, and is installed in every MLB stadium since around 2006. This system tracks the velocity, movement, release point, spin, and pitch location for every pitch thrown in baseball, allowing pitches and pitchers to be analyzed and compared at a detailed level. Major and Minor League Data Trackman Radar or PITCHf/x. Data Management. Organization Seamless integration with existing systems. Download our Fact Sheet (PDF).
At Major League Baseball’s Gameday data website, the PITCHf/x data is included in the inning and pbp/pitchers XML files. What follows is an explanation of the attributes of the pitch element within these XML files.
At stadiums without the PITCHf/x system installed, the pitch element includes only five attributes:
Stadiums with the PITCHf/x camera system have an additional twenty attributes recorded in the pitch element:
Three new fields were added to the pitch element for 2008:
Resources for this glossary included the following:
Note: Shortly after I wrote this, I found that Dr. Alan Nathan has published a better glossary than mine at his excellent Physics of Baseball site.
His freshman physics lectures on the Physics of Baseball at the University of Illinois is also an excellent primer to understanding the calculations surrounding baseball trajectories.
If you need to convert MLB.com’s player ID’s into names or Lahman database player ID’s, you can consult my list of player ID’s.
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Another common question is about the meaning of the BRK and PFX numbers reported in the Gameday application. Here’s what I wrote about the subject on another website:
There are three main forces acting on a spinning baseball: gravity, drag, and the spin force (also called the Magnus or lift force).
The drag force mainly acts to slow a pitch down, it doesn’t have much effect on the movement/break of a pitch, except for very, very slowly spinning pitches (i.e., knuckleballs).
The force of gravity is the same on all pitches, but it has a greater effect on the movement of slow pitches because it has longer to act on them before they reach the plate. Curveballs and changeups drop more due to gravity than fastballs do because they are slower pitches. The millionaire real estate agent audiobook download torrent.
Finally, the spin force acts differently on fastballs and curveballs, as the Gameday folks described. Because a fastball is thrown with backspin, the spin force pushes the ball up, counteracting to some extent the force of gravity that is pulling the ball down. This makes the fastball trajectory straighter. Because a curveball is thrown with topspin, the spin force pushes the ball down, reinforcing gravity which is also pushing it down. This makes the curveball drop even more.
Thus, the curveball trajectory has a big bend and the fastball trajectory is relatively straight. The amount of bend in the trajectory is what is being measured by the BRK parameter on Gameday.
The amount of deflection by the spin force is what is being measured by the PFX parameter on Gameday. This PFX deflection is mostly upward for a fastball, meaning that it counteracts roughly 10 or so inches of the drop due to gravity, and the PFX deflection is mostly downward for a curveball, meaning that it adds an additional 6 or so inches of drop in addition to that from gravity.
Additionally, here is a diagram, adapted from John Walsh, that illustrates the break parameters:
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Not sure what you're looking at? This page will teach you how to read the charts.
With all the different numbers and charts, it can be easy to lose track of what you're actually seeing. Each chart on this site is (or will be) summarized below.
Pitcher ChartsPitch Virtualization Top
This chart is a horizontally compressed bird's eye view of the calculated average of each pitch in the data set.
The release point is calculated back to 55 feet from home plate. This is a decent but not always accurate approximation of a typical release point.
The ball's path is calculated by plugging the acceleration and velocity data provided by MLBAM into the standard equation for acceleration: x = ax0*t^2 + vx0*t + x0.
Stock Data DownloadPitch Virtualization Side
This chart is a horizontally compressed side view of the calculated average of each pitch in the data set.
The release point is calculated back to 55 feet from home plate. This is a decent but not always accurate approximation of a typical release point.
The ball's path is calculated by plugging the acceleration and velocity data provided by MLBAM into the standard equation for acceleration: z = az0*t^2 + vz0*t + z0.
Release Points
This chart shows the vertical and horizontal position of the baseball in relation to the strikezone at 50 feet from home plate. The view is from the catcher's/batter's perspective.
At 50 feet from the plate, these positions reflect pitches that have already been released by the pitcher. For this reason, 'release point' is not an entirely accurate name for this chart.
Velocity vs Spin Angle
This chart plots pitch velocity against the direction in which the pitch is spinning.
This chart is a useful tool to help determine the accuracy of pitch type identification for the selected data.
'Spin Angle' was not added to the data set published by MLBAM until 2009, so this chart will not show any pitches from 2008. Code lyoko quest for infinity psp iso download fixed.
Spin Movement
This chart represents gravity-neutral pitch movement caused by the spin of the baseball.
Positive vertical values represent pitches that resisted gravity. Negative vertical values represent pitches that dropped faster than gravity.
Movement is charted from the catcher's/batter's perspective.
Spin Movement w/Gravity
This chart adds the effect of gravity to the Spin Movement chart. It is necessary to help represent the true movement of pitch. Slow pitches are more affected by gravity because they are in the air for a longer period of time.
The calculated effect of gravity is from 40 feet to the front edge of the plate. When I find the link to the correct explanation for this, I will provide it.
Pitch Locations
This chart shows the locations of pitches as they crossed the plate. View is from the catcher's/batter's perspective.
Pitch heights are normalized to the PITCHf/x operator's selected strikezone heights. For each batter, a human operator sets the top and bottom of the strike zone. There is room for error, but this method puts the strikezone of a tall batter in perspective with that of a short batter.
Called Strike Zone
This chart shows the locations of pitches as they crossed the plate as balls or strikes. View is from the catcher's/batter's perspective.
This chart only shows balls and strikes as called by an umpire. By its nature, this chart only shows pitches at which the batter did not swing.
Pitch heights are normalized to the PITCHf/x operator's selected strikezone heights. For each batter, a human operator sets the top and bottom of the strike zone. There is room for error, but this method puts the strikezone of a tall batter in perspective with that of a short batter.
Batter ChartsSpray Chart
This chart shows batted ball locations overlaid on a diagram of the batter's home ballpark.
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This chart is not normalized. Dimensions and locations of field landmarks (home plate, foul lines, etc.) vary from park to park. Because of this, batted ball locations from other ballparks do not map perfectly.
![]() Swing Pitch Types
This chart shows the locations of pitches as they crossed the plate. View is from the catcher's/batter's perspective.
This chart only shows pitches swung at by the batter.
Pitch heights are normalized to the PITCHf/x operator's selected strikezone heights. For each batter, a human operator sets the top and bottom of the strike zone. There is room for error, but this method puts the strikezone of a tall batter in perspective with that of a short batter.
Take Pitch Types
This chart shows the locations of pitches as they crossed the plate. View is from the catcher's/batter's perspective.
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This chart only shows pitches taken by the batter.
Pitch heights are normalized to the PITCHf/x operator's selected strikezone heights. For each batter, a human operator sets the top and bottom of the strike zone. There is room for error, but this method puts the strikezone of a tall batter in perspective with that of a short batter.
Called Strike Zone
This chart shows the locations of pitches as they crossed the plate as balls or strikes. View is from the catcher's/batter's perspective.
This chart only shows balls and strikes as called by an umpire. By its nature, this chart only shows pitches at which the batter did not swing.
Pitch heights are normalized to the PITCHf/x operator's selected strikezone heights. For each batter, a human operator sets the top and bottom of the strike zone. There is room for error, but this method puts the strikezone of a tall batter in perspective with that of a short batter.
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