question: protected char checkZone ( char zone ) { zone = Character . toUpperCase ( zone ) ; if ( zone != 'N' && zone != 'S' ) { throw new NumberFormatException ( "Invalid UTMPoint zone letter: " + zone ) ; } return zone ; }
target:  Method that provides a check for UTM zone letters. Returns an uppercase version of any valid letter passed in, 'N' or 'S'.