I've been looking into game development and reading into how the games are created. It seems most areas in games that are made to be real places are based on the real places from photographs or other sources etc. Then with the help of art directors who add things to make the areas seem more aesthetically pleasing the areas comes to life with colours and features. Things are then shifted around to make the areas more playable as games.
The majority of areas seem to start with simple sketches based on photographs or things sourced from the 'real' world. It seems there are two categories in this respect, a little like books, fiction, non-fiction but with games, the real, or the fantasy.
