Hi, you have to know that the game The Witcher was based on the book of Polish writer Andrzej Sapkowski. Andrzej modeled mainly on Slavic myths and legends, and the Witcher's action was taking place in today's Poland, Germany and neighboring countries.
Today I went on a trip to a small village in Poland near Piwniczna town where my grandmother lives and I noticed that the landscapes there are similar to those in The Witcher. Check out it!
And now look at this:
Of course they are not identical, but in my opinion they are similar :)