Read a declared fan chart: one point per mark of the median line, carrying
the median at level 0.5 and each band's two edges at their levels.
A band is matched to the median by position, as a survival curve's band
is, since a band routinely starts later or ends earlier than the line it
surrounds; where it draws nothing, both its quantiles are a gap there.
Read a declared fan chart: one point per mark of the median line, carrying the median at level 0.5 and each band's two edges at their levels.
A band is matched to the median by position, as a survival curve's band is, since a band routinely starts later or ends earlier than the line it surrounds; where it draws nothing, both its quantiles are a gap there.