Great Britain. War Office. General Staff. Geographical Section. Provisional G.S.G.S. 3980. United States. Army Map Service. Libya--Tripolitana. Alternate title: 1:100,000 Tripoli. Sheet 1768, Bir Zar. Relief shown by 25 metres and 5 metre (approximate) contour interval and spot heights. Reproduced by Great Britain. Army. Royal Engineers. Field Survey Coy., 512 (A. Fd. Svy) Coy R. E. from Italian 1:100,000 sheet, Cabao, published by the Istituto Geografico Militare, 1938. Map is part of a set of 31 sheets.