GSGS series 4414. Sheet 3914, Second Edition (A.E.F.). Copied from German Topographisce Karte 1:25,000 Sheet 3914 dated 1936. Area indicated on reliability diagram revised from Air Photographs, October '44, by 21 A. Gp. Air Survey Group. The Nord de Guerre grid on this sheet is based on the French Geographical System or graticule. The geographical values of the sheet corners and graticules tick marks on this sheet are based on the German Geographical System or graticule. To convert German Geographical values to French Geographical values subtract 1.3' from German Latitudes and add 3.15" to German Longitudes. Lambert modified conical orthomorphic projection. Nord de Guerre Grid.