Automatic

The choice of MGRS lettering scheme is based on the datum and ellipsoid of the spatial reference provided. Spatial references with new datums (e.g. WGS 84) assume new lettering scheme (AA scheme). This is equivalent to MgrsConversionMode.New180InZone60. Spatial references with older datums (e.g. Clarke 1866, Bessel 1841, Clarke 1880) assume old lettering scheme (AL scheme). This is equivalent to MgrsConversionMode.Old180InZone60. When converted, points with longitude of exactly 180deg are placed in zone 60.