'Autoformat the date labels.  The default format is the one to use
if none of the values in ``self.scaled`` are greater than the unit
returned by ``locator._get_unit()``.'

def __init__(self, locator, tz=None, defaultfmt=u'%Y-%m-%d'):

    self._locator = locator
    self._tz = tz
    self.defaultfmt = defaultfmt
    self._formatter = DateFormatter(self.defaultfmt, tz)
    self.scaled = {DAYS_PER_YEAR: rcParams[u'date.autoformatter.year'], DAYS_PER_MONTH: rcParams[u'date.autoformatter.month'], 1.0: rcParams[u'date.autoformatter.day'], (1.0 / HOURS_PER_DAY): rcParams[u'date.autoformatter.hour'], (1.0 / MINUTES_PER_DAY): rcParams[u'date.autoformatter.minute'], (1.0 / SEC_PER_DAY): rcParams[u'date.autoformatter.second'], (1.0 / MUSECONDS_PER_DAY): rcParams[u'date.autoformatter.microsecond']}
