Back in early 2014, Steve Pousty asked me if I had Lat/Longs for Major/Minor League ballparks. I pushed up a Gist and then realized this was a project worth putting effort into and defined the original goal to get all professional baseball team ballparks in GeoJSON format. I'm using Wikipedia to define "Professional Baseball" but it is only for a guide. My initial goal was to get all the North and South American teams (majors to rookie) mapped and then top tier teams from around the world. Below is a list of teams that have been mapped, ones that are currently being worked on and a to-do list. If you know of any teams outside of the New World that hasn't been mapped or isn't in the list below, I encourage you to add it so we can get it in. Right now we're only using points to map the stadiums.
There are over 450 ballparks around the world included. If you find a league I haven't added yet, please fork and add it in yourself.
I've put some thought into fixing this dataset some more. Right now teams drive the data, not stadiums. This should be resolved asap. Stay tuned for more.