Creating an Animated ShotMap with NHL’s Stats API

Using R and NHL’s stats API, I created an animated ShotMap of McDavid’s 409 recorded shots between his debut game and the end of the 2018 season.

Github repo

Getting NHL Play by Play data from the API

## Function returns URL for team's schedule between given dates
gen_url_pks <- function(teamId,date1,date2){
  URL <- paste('http://statsapi.web.nhl.com/api/v1/schedule?teamId=',teamId,'&startDate=',date1,'&endDate=',date2, sep = "")
  return(URL)
}

## Function returns URL for game data
get_url_pbp <- function(gameId){
  URL <- paste('https://statsapi.web.nhl.com/api/v1/game/',gameId,'/feed/live',sep = "")
  return(URL)
}

## Get data from NHL API
data_raw <- content(GET(gen_url_pks('22','2015-10-01','2018-07-01')))

data_tib <- enframe(unlist(data_raw$dates)) #Turn raw data into organized tibble
data_tib <- data_tib %>% separate(name, into = c(paste0("x", 1:5)),fill = "right")

gameIds <- data_tib %>% filter(x2 == "gamePk") #Extract gameIds
gameIds_list <- as.list(gameIds$value)

Extracting useful data

##Create list of player's shots from game list##
player_shots <- list()
for (gameId in gameIds_list) {
  print(gameId)
  pbp_raw <- content(GET(get_url_pbp(gameId)))
  
  #Get all Shot type events
  pbp_events <- pbp_raw$liveData$plays$allPlays
  shot_events <- list()
  for (substring in pbp_events) {
    if (substring$result$event %in% c('Shot','Missed Shot','Goal')) {
      shot_events[[length(shot_events)+1]] <- substring
    }
  }
  
  #Filter out player
  for (substring in shot_events) {
    if (substring$players[[1]]$player$fullName == 'Connor McDavid') { ### Hard coded player name | TO FIX
      player_shots[[length(player_shots)+1]] <- substring
    }
  }
}

##Filter data into organized tibble##
player_tibs <- tibble(shotId = numeric(),
                      date = date(),
                      type = character(),
                      secondaryType = character(),
                      x = numeric(),
                      y = numeric())

for (shot_event in player_shots) {
  player_tibs <- add_row(player_tibs,
                        shotId = nrow(player_tibs) + 1,
                        date = shot_event$about$dateTime,
                        type = shot_event$result$event,
                        secondaryType = if (is.null(shot_event$result$secondaryType)) {'N/A'}
                          else {
                            shot_event$result$secondaryType
                        },
                        x = if (is.null(shot_event$coordinates$x)) {
                          75
                          } else if (shot_event$coordinates$x < 0) { #Flip neg x cords
                            -shot_event$coordinates$x
                          } else {
                            shot_event$coordinates$x
                          }, 
                        y = if (is.null(shot_event$coordinates$y)) {
                          5
                          } else if (shot_event$coordinates$x < 0) { #Flip y cords when x is neg
                            -shot_event$coordinates$y
                          } else {
                            shot_event$coordinates$y
                          })
                        }

Animation with ggplot2 and gganimation

##Create plot and base animation
bg_img <- png::readPNG('bgB.png')
p2 <- ggplot(player_tibs, aes(x,y,group=date, color = type))+
  
  coord_fixed(ratio = 1,xlim = c(0, 100), ylim = c(-42.5,42.5))+
  scale_x_continuous(expand = c(0, 0)) + scale_y_continuous(expand = c(0, 0))+
  background_image(bg_img)+

  theme(
    panel.background = element_rect(fill = "transparent"),
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank(),
    plot.title = element_text(size = 24, face = "bold"),
    plot.subtitle = element_text(size = 16),
    plot.caption = element_text(size = 12),
    plot.background = element_rect(fill = "transparent", color = NA),
    axis.line = element_blank(),
    axis.ticks = element_line(size = 1),
    axis.ticks.length = unit(.2, "cm"),
    axis.text = element_text(size=12),
    axis.title = element_text(size = 16, face = "bold"),
    legend.background = element_rect(fill = "transparent"),
    legend.box.background = element_rect(fill = "transparent"),
    legend.key = element_rect(fill = "transparent"),
    legend.text = element_text(size = 12),
    legend.title = element_blank())+
  
  scale_color_manual(values = c("#5EB32D", "#CC7952", "#A2E5FF"))+
  
  labs(title = "McDavid ShotMap 2015/16 - 2017/18",
       subtitle = "Shot: #{next_state}",
       caption = "Michael Diaz \n 
       Data source: NHL | Background adapted from 'Completefailure', released BY-SA 3.0")+
  
  geom_point(alpha = 1, size = 8, stroke = 1)+
  transition_states(shotId)+
  shadow_mark(past = TRUE, future = FALSE, size = 4, alpha = .4)


animate(p2,
        detail = 2,
        nframes = 904, #(frames x 2)
        fps = 25,
        height = 600,
        width = 600)

anim_save(paste('ShotMap_McDavid',Sys.Date(),'25.gif', sep = ""),animation = last_animation())

API copyright notice: NHL and the NHL Shield are registered trademarks of the National Hockey League. NHL and NHL team marks are the property of the NHL and its teams. © NHL 2019. All Rights Reserved.