Provisional GSGS series 4228. First Edition-AMS 1. Copied from a Gela 1:50,000 map dated 1932 with principal communications revised to 1940 using air photos. The meridians are based on the meridian of Rome, which is 12 degrees, 27 minutes and 7.1 seconds east of Greenwich. Contours at 25 metres interval. South Italy Grid "Blue".