Save_Ferris
Admiring Myself
Does it have to do with transportation? Because it looks like railways...
Correct.My first thought was that it's tennis related, but I don't think that's true now due to the presence of Bulgaria and the absence of the UK.
Will guess anyway: grand slams won?
Very correct. Yellow 1-10 titles, Orange/Red, more than 10.Something the US, Australia, Spain, Switzerland, and the Czech Republic are all good at (or at least one person from that country is good at this.) Must be Tennis.
Gray - no one from this country has ever won a men's Grand Slam tournament in the open era.
Yellow - At least one person from this country has won a men's Grand Slam tournament in the open era.
Red - This country has a large amount (10?) of men's grand slam championships in the open era.
edit: @Arwon: Britain has several Wimbledon titles, but none are in the open era.
Nastase!Romania is odd if it is tennis.
Is there some relevance to only the Western Hemisphere being provided?
The Eastern Hemisphere would make the map way too easy.
Well give the full map once someone has guessed the correct answer, so we can compare if that is correct.