Author: OBSERVATOIRE CENTRAL DE L'INDOCHINE.
Title: Code de Signaux Sémaphoriques.
Description: Hanoi: Imp. d'Extrême Oriet, 1931. Single sheet, 760 x 555 mm., old folds with a couple of tears with no loss on folds. Rare. An innovative typhoon tracking map using the optical telegraph [semaphore] to transmit data from remote monitoring stations to the central observatory at Phu-Lién, northern Vietnam. The optical telegraph used a series of shapes and colours to transmit information and although superseded in most areas, it was a boon in territory where laying and maintaining a wired system of telegraphy was problematic.

Keywords: Maps


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