in GTA... it has been confirmed that they're are 3 major cities...Los Santos (Los Angeles), Las Ventura (Las Vegas) and San Fiero (San Fransisco)...
there are also going to be 12 small towns you have to drive through to get to these other locations...
right now the map look semi like this.... (this is not official but is a rough outline of where things are situated)
now if you look at the bottom left corner you'll see the city of Los Santos...
here is the confirmed map of Los Santos...
it is 1/5 the size of the entire game..
now if this game isnt going to be the biggest game to this date...
i dont know what is...