Although, now that I've done more digging, it looks like they're using satellite imagery for at least some of this, along with LIDAR and infrared techniques: http://static.googleusercontent.com/external_content/untrust...
Although, now that I've done more digging, it looks like they're using satellite imagery for at least some of this, along with LIDAR and infrared techniques: http://static.googleusercontent.com/external_content/untrust...