Here is the map of Chicago from Watch_Dogs:
And here is the map of Chicago from Google Maps:
As you see, these maps don't have much in common. When seen from a birds-eye perspective there isn't even a superfluous similarity. You will also notice that the map from Watch_Dogs is tiny compared to real-world Chicago. Actually, Watch_Dogs Chicago has barely the size of a small town. Yet, it feels like a real metropolis.
How did the artists and mappers pull this off?
They picking the most distinguished and iconic places in Chicago and replicating them by hand in 3d modeling programs. I am quite sure that they worked based on photos, likely even visited Chicago themselves to get an own impression of the real-world places.
Then they moved them as closely together as possible without them blending too much into each other and placed a few generic buildings between them as separators. The result is a map which still feels like real Chicago and lets the player find a lot of famous sights, even though it only has a tiny fraction of the size of the real Chicago.
You might wonder: Why were they so lazy? Why didn't they recreate all of Chicago? There are several reasons for that:
- Budget constraints. Watch_Dogs already was a AAA title with a million dollar budget. They had a whole army of 3d artists working on the game for years. Yet, creating a city the size of real Chicago with that level of detail and variation was still far from humanly possible.
- Technical constraints. Even when it would have been possible to create all that (maybe through procedural generation based on map data), it might simply not have been possible to simulate such a huge world on present-day hardware.
- Gameplay considerations. Let's be honest: Most parts of a real-world metropole are boring. In a real city you have blocks after blocks of office and residential buildings without anything extraordinary to them. And with the typical grid-layout of most North-American cities it is not even very interesting to navigate. But by only focusing on the most interesting parts of it, you can create a world which is far more interesting to explore. You find something interesting literally at every street corner.
- It would not have been worth it anyway. According to Steam, the game occupied me for 52 hours. And seriously, that was more than enough. The main story was already overstretched, I had mastered all the game mechanics and the optional challenges had already gotten dull, too. Honestly, I was glad the game was over. But that was also the point where I had explored most of the game world. I can say with confidence that I have seen and appreciated at least 80% of the work of the map team. And I think they did a fantastic job (better than that of the writers and game designers, at least). But when the game would have taken place in a real-size Chicago, I would have still seen only a glimpse of the whole city. And with the gameplay being exhausted, I wouldn't really have felt like exploring it all. That means most of their work would have been in vain.
No, Watch_Dogs Chicago is exactly the right size. Not too small but not too large either.