Series Number Id: GSGS 3389. Sheet number: part of sheet 51. Battle of Arras preparations; trench target and hostile battery map 5-3-17. "3rd Field Survey Coy R.E. (1403)." "Ordnance Survey, February 1917." Grey base map. German trenches and names red; British trenches to depth of 300 yards blue. Overprint in purple: [artillery intelligence], [target and hostile battery], artillery details. Overprint in green: [enemy organisation] reference; railways, roads and tracks chiefly used, and more., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC21; envelope_number: 668.