I used an excellent library called OverlappingMarkerSpiderfier. You can find the code on github here: https://github.com/jawj/OverlappingMarkerSpiderfier https

I used an excellent library called OverlappingMarkerSpiderfier. You can find the code on github here: https://github.com/jawj/OverlappingMarkerSpiderfier https://github.com/jawj/OverlappingMarkerSpiderfier There's also a link in the credits.