digital maps that know all about walking speeds sound like a pretty good idea. i’m pleased to hear that they’ve figured out that rivers are kind of major boundaries: when i lived on the north bank of the river tyne utilities like up my street continually pointed me to amenities less than a mile away on the south bank of the tyne that were a long drive by toll tunnel and an even longer drive by free bridge.

The end result is a bubble diagram showing how far you can roam and still get to your destination in time.

“The bubble is not a perfect circle as the software is taking account of actual street patterns and the physical features of the city,” explained Mr Donovan.

a motoring version that keeps up to date with traffic jams, real traffic speed, road closures etc would be even more useful though.