Highcharts - navigation by 3rd element in series &

Question

I have some info which is in this format (speed, frequency, date). What happens is that I need to plot this chart with speed x frequency, but I want to allow the users to use the navigation filtering by the date, which is not appearing on the chart.

Also, I have some info which is not built dynamically, which is the limits of speed x frequency. This info will be fixed as reference points on the plot. So, when I filter the plot info (not the limits), it must always display these limit plots.

You can have an idea by this chart, the area plots show the limits for the points (speed, frequency). Then, I would add points of speed x frequency (x date), and filter then by date.

Can you guys give me some advice on this?

here is a JSFIDDLE

JSFIDDLE

data: [
                [0, 20, here is a date], [10, 20,here is a date],
                [50, 39.9994, here is a date], [100,49.7494, here is a date]
            ],

Guys, notice that every element of the array in the series has 3 elements [a, b, c], suppose the third one (c) is a DATE and not a random number as it is right now. I want to be able to use the commented the navigator code to filter this series by this C element, which doesn't in fact appear on the chart you see, it is a hidden element, just to filter the data.

Answer 1

There will be a little tricky, if you want to have a navigator in the same chart. Navigator works only with datetime data and it must be connected with the axis from the main chart.

So, you have data in that format:

var points = [
  [5, 9, Date.UTC(2016, 1, 0)],
  [65, 6, Date.UTC(2016, 1, 1)],
  ...

You need two x axes - one which represents the data and the other which is connected to the navigator. The second axis must be visible to work with the navigator and must be connected with the datetime data.

So now, except two x axes, you need two series - one with the actual data, and the other consists of [date, y] values from the first series. The additional data will be visible in the navigator - note, that in the navigator you cannot use scatter series - so it will be converted to line series - to happen it without errors, your data should be sorted by date.

series: [{
  id: 'main-series',
  data: points.map(function(point) {
    return [point[0], point[1], point[2], point[1]]
  }),
  showInNavigator: false,
  xAxis: 1,
  keys: ['x', 'y', 'date', 'holdY'] //holdY is for easier hiding points
}, {
  xAxis: 0,
  data: points.map(function(point) {
    return [point[2], point[1]];
  }),
  showInNavigator: true,
  enableMouseTracking: false,
  color: 'transparent',
  showInLegend: false
}],

xAxis: [{
  minRange: 1000 * 3600 * 24,
  type: 'datetime',
  tickLength: 0,
  tickLength: 0,
  labels: {
    enabled: false
  },
}, {
  type: 'linear'
}],

The last thing you need a callback which will hide/show points after the extremes in the navigator are set. Hiding/showing depends on the third point's property which is date. There is no directly API to hide/show specific points (except pie), but it can be achieved by setting point's value to null (that is why I preserved the real y in holdY).

events: {
  afterSetExtremes: function(e) {
    var points = this.chart.get('main-series').points;
    points.forEach(function(point) {
      point.update({
        y: e.min <= point.date && point.date <= e.max ? point.holdY : null
      }, false, false);
    });
    this.chart.redraw();
  }
}

example: https://jsfiddle.net/3wuwdonn/1/

I would consider using a navigator as a separate chart, then you wouldn't need the second x axis and series in the main chart and you wouldn't need to make them look invisible.

example with a navigator only chart here: http://jsfiddle.net/f7Y9p/