As the generation near its end, game worlds continue to grow larger. Over on Reddit, user jayzpoptart compared Franklin's location from the Grand Theft Auto 5 trailer and found the spot on the full map blueprint. After finding the location on blueprint, you will notice the small size Vespucci Beach in comparison to the huge map.
If you watch the latest GTA 5 gameplay trailer, you will see Franklin exit a store as he walks by a sunglasses stand towards "Sidewalk Market" sign in the distance. If you look at the Game Informer screenshot, you can see the same sunglasses stand and "Sidewalk Market" sign. Now take note of the size of the location.
As the camera follows Franklin in the trailer, the camera then zooms out to an overhead perspective of the city. If you look closely at both the overhead view in the trailer and blue print, you will see the same round building or structure near the coast of the beach.
After finding the location on the map, you can pinpoint the stretch of store fronts near the beach to the blueprint map. What seems like a rather large location only shrinks in comparison to the actual map.