my $tempmin = Chart::Gnuplot::DataSet->new(
   xdata => \@yfix,
   ydata => \@minit,
   style => "lines",
   color => "dark-gray",
   linetype => "dash",
   width => 1,
);

my $tempmax = Chart::Gnuplot::DataSet->new(
   xdata => \@yfix,
   ydata => \@maxit,
   style => "lines",
   color => "dark-gray",
   linetype => "dash",
   width => 1,
);