Highcharts, how can I start xAxis on an arbitrary time

Question

I have a line chart with a datetime xAxis. I need to show ticks every 10 minutes, for that I have set tickInterval to 10*60*1000, my problem is that I need to show ticks every 10 minutes since the first date, for example, if my first point is displayed at 10:33, I need to show ticks at 10:33, 10:43, 10:53, etc, but what I have are ticks at 10:30, 10:40, 10:50 and so on, is there any way to do this?

Thanks!

Greg Ross Greg Ross · Accepted Answer · 2012-11-01T01:20:47

It's not that straightforward because Highcharts automatically determines the labels to use when the x-axis is of the type 'datetime':

"In a datetime axis, the numbers are given in milliseconds, and tick marks are placed on appropriate values like full hours or days"

To set labels like '10:33' you need to create your own categories. Luckily these can simply be derived from your data and the desired time interval.

Here's a working example: http://jsfiddle.net/Rt7ZV/

We just take the given start date, interval and number of points and build an array of the categories to be used as the x-axis labels.

function getTimes(numTimes, interval) {

    var ms = (new Date(2012, 02, 30, 10, 33)).getTime();
    var times = [];
    var startDate = new Date(ms);
    times.push(startDate.getHours() + ":" + startDate.getMinutes());

    for (var i = 1; i< numTimes; i++)
    {
        ms += interval;
        var nextTime = (new Date()).setTime(ms);
        var nextDate = new Date(nextTime);
        times.push(nextDate.getHours() + ":" + pad(nextDate.getMinutes(), 2));
    }

    return times;

}

function pad(num, size) {
    var s = num+"";
    while (s.length < size) s = "0" + s;
    return s;
}

var data = [1, 2, 3, 4, 5, 3, 2, 5, 7, 6, 4];
var interval = 10*60*1000
var timeCategories = getTimes(data.length, interval);

$(function () {
    var chart;
    $(document).ready(function() {
        chart = new Highcharts.Chart({
            chart: {
                renderTo: 'container',
                zoomType: 'x',
                spacingRight: 20
            },
            title: {
                text: 'Time series'
            },
            xAxis: {
                categories: timeCategories,
                title: {
                    text: null
                },
                startOnTick: false
            },
            yAxis: {
                title: {
                    text: 'Exchange rate'
                },
                startOnTick: false,
                showFirstLabel: true
            },
            tooltip: {
                shared: true
            },
            legend: {
                enabled: false
            },


            series: [{
                type: 'line',
                name: 'time series',
                data: [
                    1, 2, 3, 4, 5, 3, 2, 5, 7, 6, 4
                ]
            }]
        });
    });

});

Highcharts, how can I start xAxis on an arbitrary time

2 Answers