AMS 1 United States. Army Map Service Great Britain. War Office. General Staff. Geographical Section. G.S.G.S. no. 4380 United States. Army. Corps of Engineers In upper left margin: Italy. North Italy grid. Convergence: grid north is 1-degree 46' W of True North on this sheet. Source: Carte d'Italia 1:25,000 1935, various guide books and plans.