RoadTour OutDoors for iPhoneMapping company RoadTour has developed an application for the iPhone based on Ordnance Survey maps that can be used to guide walkers and cyclists in even the remotest locations, regardless of whether they are in range of mobile phone reception.

The RoadTour OutDoors application is described by its inventor as "the safest walking device ever". It marries its map detail with orientation information provided by the iPhone's digital compass, making it nearly impossible for the user to get lost or to misread the map information and head off in the wrong direction. RoadTour says 55 percent of customers it polled said they had been lost when out for a country walk or cycle ride, despite having a map to help them find their way. Satnavs, meanwhile, are useful only when the user is following a route or recognised route or path logged in to its database.

The OutDoors app for iPhone contains the complete OS maps of the UK, including all 22,000 sq km of national park. The OS maps are many hundred times more detailed than the average satellite navigation device used by motorists. For clarity when driving, satnav devices contain road information along with place names and road names, but omit much other visual information. They also offer POIs (points of interest) such as petrol stations, hotels, restaurants and tourist attractions, many of which are hidden unless the user specifies they should be displayed.

Ordnance Survey maps, by contrast, include every building along with relief detail and any permanent fixtures such as triangulation points that could be used to orientate the user. The OutDoors app includes 250,000 place names across the UK's 250,000 sq km expanse.

The UK's mountain rescue service costs £6m a year to run. With highly detailed, location-aware maps to guide hikers and cyclists, it's hoped fewer callouts will be required.

OutDoors costs £24.99 per region or £1.99 for a less detailed version OutDoors Lite, that covers to whole country. It can be bought from the iTunes Store.

RoadTour says it plans to launch further versions of its OutDoors app for Windows Mobile and other smartphone platforms in the coming months. More details at roadtour.co.uk.

RoadTour OutDoors for iPhone