In bayesball/CalledStrike: Functions for Graphing Statcast Data

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

library(CalledStrike)
library(dplyr)

Introduction

There are three functions for visualizing pitch locations.

The function location_compare() will graph the pitch location for a data frame or list of data frames.
The function location_count() will show the locations of pitches for a specific pitcher on a particular count.
The function location_count_compare() will graph the pitch locations for a specific pitcher for several values of the count.

Data

The package includes the dataset sc_pitchers_2019 that contains Statcast data for 20 pitchers for the 2019 season.

Pitch Locations for a List

Suppose we want to compare the locations of the fastballs thrown by Aaron Nola and Trevor Bauer.

I find the subset of data I need and then create a list dividing the data by pitcher.

d <- filter(sc_pitchers_2019, 
            pitcher %in% c(605400, 545333),
            pitch_type == "FF")
ds <- split(d, d$pitcher)
names(ds) <- c("Bauer", "Nola")

Now we can construct the graph.

location_compare(ds)

Pitch Locations for a Specific Count

Suppose we want to look at the locations of Aaron Nola’s pitches on a 0-0 count. I can find Nola’s MLBAM id number by use of the chadwick dataset (also included in the package) that contains the id numbers for all players.

chadwick %>% 
  filter(name_last == "Nola", name_first == "Aaron")

To produce the graph, type

location_count(sc_pitchers_2019, 
               605400, "Aaron Nola", "0-0")

Pitch Locations Across a Group of Counts

Suppose we want to compare Nola's pitch locations across the counts "0-0", "1-0", "0-1", "0-2"

location_count_compare(sc_pitchers_2019, 
               605400, "Aaron Nola", 
               "R", "Offspeed", 
               c("0-0", "1-0", "0-1", "0-2"))