United Kingdom. Ministry of Defence. Directorate General of Military Survey. Great Britain. Directorate of Military Survey. North Decimal Degree 18.250000. South Decimal Degree 18.0000. East Decimal Degree -88.2500. West Decimal Degree -88.5000. Standard map series designation: Series E755 (D.O.S. 4499). Transverse Mercator projection. U.T.M. zone 16 grid. Relief shown by 20 m. contour interval and spot heights.