Tuesday 18 August 2015

xG Hexagonal Maps

First popularized by Kirk Goldsberry and then introduced to hockey via War-On-Ice's Hextally plots, hexagonal plots are a great tool for helping to visualize sports. I have created my own version's below in the form of apps. Two quick caveats, my current 2014/2015 data seems to have some bugs in it so take those seasons with a grain of salt and the individual attempts map also seems to be buggy for reasons currently unknown. I am working to fix both of those issues but just keep them in mind.

Here are some of the features of my xG Hexagonal Maps:

  • If you are unfamiliar with xG (Expected Goals) you can read my post detailing the methodology here. Simply, it provides the probability of any given shot resulting in a goal. 
    • A slight change between this xG and the one from that post is that these numbers also included missed shots now
  • The size of each hexagon is the frequency of shots from that specific location. The larger the hex, the more often a player shoots from that location
  • Each hex is coloured by the efficiency (xGe) of a player/team/goalie from that specific location.
    • Efficiency here is measured as the difference between how many goals we expected them to score from that location (their xG) and how many they actually scored from that danger zone.
    • A Blue Hex means that their xG was greater than their actual G, implying that they may have under-performed. 
    • Red Hex means that their xG was less than their actual G, implying that they may have over-preformed. 
  • Danger Zones are denoted by the light-pink and light-purple lines, high/medium/low. 
  • Not every red hex means a player over-preformed and not every blue hex means a player under-preformed. If you play in front of Henrik Lundqvist, your On-Ice Against xG is probably always going to be higher than your actually goals against. 
The links to all the different maps are posted below. Please let me know if you have any thoughts, questions, concerns, suggestions find anymore bugs . You can comment below or reach me via email me here: DTMAboutHeart@gmail.com or via Twitter here: @DTMAboutHeart  

Team Attempts Map

https://dtmaboutheart.shinyapps.io/app-1

Goalie Map

https://dtmaboutheart.shinyapps.io/Tendy

Player On-Ice Attempts Map

https://dtmaboutheart.shinyapps.io/PuckOn

Player Individual Attempts Map

https://dtmaboutheart.shinyapps.io/Single