[kurtosis]

Just a guess,

The city I live in, Berlin has an area of ~821 km^2

Let's suppose that one city block is about 0.2 km x 0.2 km

This implies that there are on the order of 10 km of road per km^2 of area. Thus the length of road is O(10^4) km for one major city. Now if we drive 30 km/h, and there are ~25 intersections per km^2, and the average wait time to turn is 1 minute (I have no idea), then we need 20 + 25 ~ 45 minutes to cover 1 sq km - In reality we will not have a perfectly efficient travelling salesman route and will have to cross some streets more than once so let's say it takes 1 hour per km^2. Thus the entire city can be covered in about 821 hours per car, or about one month / car. If we only allow a 40 hour work week, then it takes about 5 months.

Thus with a modest fleet of 5 cars the city can be updated about once a month. Does this sound right? If so not bad. Of course streetview isn't working here for legal reasons, but this logic should apply to other similar cities.

[pbw]

Maybe some day they will be able to get updates from any old photographs or video taken by anyone. Automatically figure out what part of the world is in view with overlaps, like Photosynth does today, then incrementally apply updates if something is new or different. For example if a restaurant owner snaps a picture of the specials board on the sidewalk, it will figure out what exactly is new and patch just that board in the virtual world.