User blog comment:DeltaWolf247/GTA V Map Confirmed/@comment-5265910-20130913230442

The map of comparison view with San Andreas and Liberty City is obviously miscalculated, otherwise we'd have an army base that's the size of Algonquin, airport 5 times the size of Francis International and Grapeseed village as big as Los Santos from GTA:SA :D

Leaving aside the maths, I think it would be more accurate to just compare the maps by placing for example airports on top of eachother or other objects that should be of comparable sizes in both cities and assume the size from then on.