OS Explorer Map Launceston & HolsworthySheet Number 112The Explorer map series is Ordnance Surveys flagship large scale sheet map range which superseded the old Pathfinder and Outdoor Leisure series. The previous Outdoor Leisure maps are identifiable by a yellow flash on the otherwise orange cover.The Explorer maps cover most of Great Britain at a scale of 1:25 000 (1 mile to 2.5 inches) and the sheet lines are based geographically to cater for regional tourism. Many maps overlap to ensure the inclusion of key features on the edge of the coverage area. They show gardens open to the public, nature reserves, country paths, footpaths and bridleways.