The developer of Alan Wake, Remedy, did its research in order to make the game as realistic as possible by taking real life photographs of various locations.
Here are two photographs. One is from the game while the other is a real photo taken by Remedy.
The two photographs below should show you how accurate the rendering in Alan Wake really is:
Here is a real life photograph of a dam in the Diablo, Washington USA.
Here is an in-game rendered shot of Alan Wake. Notice the water and the trees in the background nearly match the real photograph seen above.
As you can see a lot of time and effort was put into creating the environments in Alan Wake. This makes for a very realistic and atmospheric gaming experience.
