Provisional GSGS series 4229. First Edition-AMS 1. Copied from an Italian Istituto Geografico Militare map dated 1935 with principal communications revised using smaller scale maps from 1937 and air photos. Compiled by the U.S. Army Map Service but photolithographed by the British Ordnance Survey in 1943. Road classification is NOT based on reconnaissance, reliability is uncertain. The meridians are based on the meridian of Rome, which is 12 degrees, 27 minutes and 7.1 seconds east of Greenwich. Contours at 50 metres interval. North Italy Zone Grid.