I like this feature! I'm just now getting into spray charts and I thought I would use this thread for a few questions, perhaps (after doing some due diligence with search and not finding much information).
First question: The acronyms (GO, FO, etc.) are obvious and I know what EV is. I also know that the batted ball locations adhere to the Retrosheet diagram. But in this diagram, for this home run, what does "BS2" mean?
Second question: I notice that spray charts are "wiped" at the end of each season. The one that you are looking at here is for spring training; will it reset for the regular season or will it include spring training for the rest of the year?
By the way, elsewhere Matt linked to the diagram at Retrosheet but this one that I found awhile back is easier to read and a bit more comprehensive: