Einar Öberg, Technical Director at North Kingdom put together a lovely experiment that generatively adds trees, ferns and other jungle-like matter to Google Street View. What’s particularly nice about it is that the effect has appropriate depth – vegetation scales back toward the horizon as if it were in the photo all along, and of course you can move and pan around. He explains the technique himself:
This experiment using an undocumented part of Street View, the depth data. With that a depth map and a normal map is generated, which can be used in the shaders and to plot geometry and sprites in (almost) the correct position in 3d space.
UPDATE: Here’s a writeup by Einar himself on the technical details.