Bing Maps App
You may not have even realised, but there is an app on windows called maps. This is powered, of course, by Bing Maps. Click on the menu in the top right and you'll see an option called 3D cities.
These are the cities that Bing maps has captured photogrammetry imaging for.
Flight simulator is a bit of a mish-mash of techniques. The 3D cities around the world that have been captured are rendered as such in the game. Not tremendous detail, but for the purpose of a flight simulator, really good. Then you have the AI generated content, that detects trees, buildings etc from a flat map and places generic models in their place. These models are geographically representative, so different countries will have different types of building, typical of the area, placed. Again, on the whole, this works great from up high but there are inevitably errors. For example, my hometown of Plymouth has a Lido on the seafront. That lido is a building in the game. Football Stadiums tend to turn into office blocks with a nice patch of green in the middle.
Then the final technique is the rendered model of specific landmarks. Paris and London is a good example of this. The city isn't 3D mapped, but does have many of the iconic buildings represented in very high quality models on the map.
What myself and a number of others have been doing is using the Google data to overlay on the game. This only applies to the local version of the game obviously, but allows you to fix some of these AI generated issues, especially in areas you might fly around regularly. It started off with just landmarks, but is now much easier to do with large areas of the map. You do get a somewhat jarring experience moving from google map data to the game generated landscape though.
It needs to be said, that I think Microsoft expected this, as they provided a publicly available SDK and Dev mode with which to do all this, and it's surprisingly simple. So I don't think too much mud should be slung at Asobo.
And regardless of the mapping issues, it's still one of the most visually stunning sims out there in my opinion. It's a 10 year project and I look forward to watching it grow and develop.