I found this jsfiddle and I'd like to implement that after the series had been created. often I let the user update the chart, I do this by sending array of float to the setData function of the series.
for example:
//Build the area values
for (var i = 0; i < area.length; i++)
{
areaValues.push(parseFloat(area[i]));
}
chart.series[2].setData(areaValues,false);
chart.redraw();
Is there any way to add flags before the redraw without recreating the chart?
The problem is in your data format - for flags should be this one:
Not just a number. You can achieve what you need in a two ways, or by setting new data, or adding new series, see example of both: http://jsfiddle.net/sH777/180/