GSGS series 4228. Second Edition (coloured). Italian Istituto Geografico Militare map dated 1925 and photolithographed by the British Ordnance Survey in 1936. The meridians are based on the meridian of Rome, which is 12 degrees, 27 minutes and 7.1 seconds east of Greenwich. Contours at 10 metres (V.I.). South Italy Grid.