Britain's famed Ordnance Survey, the hyper-accurate maps of the whole country and all its public rights-of-way for walkers, is about to get a 21st-century tool for getting directions.
The maps have been regularly updated over the years, but the rule for calculating the time it takes to walk a given route hasn't really changed since William Naismith, founder of the Scottish Mountaineering Club, set out the rule that allows “an hour for every three miles on the map, with an additional hour for every 2,000 feet of ascent.”
Naismith's rule, which has had many fudges and kludges attached to it over the years, will give way in August to a new algorithm that will be incorporated in the app version of the maps. No details have been released, but it will make adjustments for downhill walking, for different types of paths and recent experiences. The Guardian (UK) has a fuller article, with more details and a dose of hiker humor.