Map the un-known

so i've sparked an interest in map making again, i got into it a while back for a bit, and then moved on as is my nature. BUT i was looking for "map building" software and found this "google map maker" which is for, i guess, small countries to map out there own roads and stuff... but i was wondering... google being all open source like it is, why it doesn't let someone create fictional google earth, where you can look up your favorite fictional world, and look around a high quality map of it in the google earth style... i think this is a great idea, there are TONS of fictional worlds out there with maps and cities and all such things, and TONS of nerds who'd be happy to create them given the tools. i say, "GOOGLE! give us the tools! let us create fictional worlds!"