Based on other previous leaks, it's possible the large map is Vice City and its surrounding area while the smaller islands are various Caribbean islands.
It doesn't reveal much, but when you piece the various leaks together, they show three large landmasses featuring more than one large city and a variety of smaller islands.
Multiple leakers -- reliable and non-reliable -- have said the game's central location is Vice City, the series fictional take on Miami.These images seem to lend credence to the game being set in Vice City and the surrounding Caribbean, but that's only if they are legit.