Frustratingly, they don't explain how it works, or why it useful. 1) its a visual search. This means that using streetview data, google has crunched a sparse 3

Frustratingly, they don't explain how it works, or why it useful. 1) its a visual search. This means that using streetview data, google has crunched a sparse 3d pointcloud. Each of these points are represent a globally unique has of a point. (a global descriptor) 2) This is better than GPS, because its possible to resolve a position to ~20cms and crucially where true north is. Crucially it doesn't need an unobstructed view of the sky to resolve a position. In urban canyons, where sky is limited, there are loads of unique visual points that are more than enough to calculate an accurate position. It also works inside, in places like malls. The drawback is that it requires constant updating to remain accurate, buildings and hoardings change. Now, there is a patent for self updating, but google doesn't own it. Also, they don't appear to be offering this service to third parties, which is a shame.