Users set up a digital account to download map portions straight to their device. There is a choice of Landranger (1:50,000) or Explorer (1:25,000) scales.
Both show footpaths, bridleways and topographic data, but Explorer shows woodland, copses, buildings and field boundaries in detail, making it more suited to land management. The maps are held on the phone's memory so users can still access them when they do not have reception.
The cost varies but 25,000sq km of Landranger mapping costs £12.50 - and that is enough to download the whole of Wales. See www.memory-map.co.uk.