Disregard anything relating to Outerra. If one looks at the images posted, they depict images so crude that even GT5's outdated maps like Trial Mountain look two console generations more advanced. A rough approximation isn't good enough. For use in a video game, the maps have to be in intimate detail, rather than just generalized terrain with some generic trees scattered about. Google's satellite imagery isn't anywhere near good enough, either. It's one thing when you're hovering above a city in Google Earth, but another when you're trying to use those images at eye level. Rendering a racing game using Google satellite maps would make the terrain look like it's rendered in a Nintendo 64 game.
Nobody anywhere has maps of such minute detail that they would be useful in the way we're discussing here. We need hyper-detailed textures, not fuzzy textures taken from miles up in the air. We need terrain rendered in tiny details down to feet and inches with even two-inch bumps rendered in detail rather than just several-foot-wide polygons approximating the ground and tarmac. We need all the little things along the track like kerbs, signs, guard rails, shrubs and flowers, and so forth all rendered in detail.
Having tracks modeled in game-worthy detail takes thousands of hours of labor for a single two or three-mile course, and vast amounts of disc space. Having just an entire city rendered like this would probably be terabytes of information. Having an entire county would be even more mind-boggling. Then there's the absurdity of rendering an entire state like this, which isn't nearly as nonsensical as the whole US. I can't find words sufficient for mocking notions of Gran Turismo Earth.
Let me know when someone gets Bathurst rendered in Outerra in such detail that, when viewed at eye level, it's hard to tell that you aren't looking at the real thing, when we have every inch of the track rendered in inch-by-inch detail. After we've got that, we'll discuss what time and effort when into putting it together, and then we'll talk about how much it would take to render enormous amounts of terrain in this level of detail.