Before revision: The precise spacing is defined by dividing the world into zones based on latitude, and is given in the following table: zone latitude range level 0 (arc secs) level 1 (arc secs) level 2 (arc secs) latitude spacing all 0°–90° (North–South) 30 3 1 longitude spacing I 0°–50° ( North – South ) 30 3 1 II 50°–70° ( North – South ) 60 6 2 III 70°–75° ( North – South ) 90 9 3 IV 75°–80° ( North – South ) 120 12 4 V 80°–90° ( North – South ) 180 18 6 In addition three more levels (3, 4 and 5) at increasing resolution have been proposed, but not yet standardized.
After revision: The precise spacing is defined by dividing the world into zones based on latitude, and is given in the following table: zone latitude range level 0 (arc secs) level 1 (arc secs) level 2 (arc secs) latitude spacing all 0°–90° (East–West) 30 3 1 longitude spacing I 0°–50° ( East – West ) 30 3 1 II 50°–70° ( East – West ) 60 6 2 III 70°–75° ( East – West ) 90 9 3 IV 75°–80° ( East – West ) 120 12 4 V 80°–90° ( North – South ) 180 18 6 In addition three more levels (3, 4 and 5) at increasing resolution have been proposed, but not yet standardized.