GSGS series 4414. Sheet 4309, Third Edition (A.E.F.). First edition copied from German Topographisce Karte 1:25,000 Sheet 4309 dated 1931. Second edition revised from air photographs October 1944 (521 R.E.). Third edition revised from air photographs February 1945 (521 R.E.). Lambert modified conical orthomorphic projection. Nord de Guerre Grid.
