code: function getLetterDesignator(latitude) {
    if (latitude <= 84 && latitude >= 72) {
      // the X band is 12 degrees high
      return 'X';
    } else if (latitude < 72 || latitude >= -80) {
      // Latitude bands are lettered C through X, excluding I and O
      const bandLetters = 'CDEFGHJKLMNPQRSTUVWX';
      const bandHeight = 8;
      const minLatitude = -80;
      const index = Math.floor((latitude - minLatitude) / bandHeight);
      return bandLetters[index];
    } else if (latitude > 84 || latitude < -80) {
      //This is here as an error flag to show that the Latitude is
      //outside MGRS limits
      return 'Z';
    }
  }
docs: Calculates the MGRS letter designator for the given latitude.
  
  @private
  @param {number} lat The latitude in WGS84 to get the letter designator
  for.
  @return {char} The letter designator.