getLetterDesignator static method Null safety

String getLetterDesignator(
  1. double latitude
)

Calculates the MGRS letter designator for the given latitude.

@private (Not intended for public API, only exported for testing.) @param {number} latitude The latitude in WGS84 to get the letter designator for. @return {string} The letter designator.

Implementation

static String getLetterDesignator(double 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;
    var index = ((latitude - minLatitude) / bandHeight).floor();
    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';
  }
}