Line chart with 500k points

author(s): Torstein Hønsi

by maritavindedal

HTML

<script src="https://github.highcharts.com/enhancement/export-data-loading/highcharts.js"></script>
<script src="https://github.highcharts.com/enhancement/export-data-loading/modules/exporting.js"></script>
<script src="https://github.highcharts.com/enhancement/export-data-loading/modules/export-data.js"></script>
<script src="https://code.highcharts.com/modules/accessibility.js"></script>

<figure class="highcharts-figure">
    <div id="container"></div>
    <p class="highcharts-description">
        Using the Highcharts Boost module, it is possible to render large amounts
        of data on the client side. This chart shows a line series with 500,000
        data points. The points represent hourly data since 1965. Click and drag
        in the chart to zoom in.
    </p>
</figure>

CSS

.highcharts-figure,
.highcharts-data-table table {
    min-width: 360px;
    max-width: 800px;
    margin: 1em auto;
}

.highcharts-data-table table {
    font-family: Verdana, sans-serif;
    border-collapse: collapse;
    border: 1px solid #ebebeb;
    margin: 10px auto;
    text-align: center;
    width: 100%;
    max-width: 500px;
}

.highcharts-data-table caption {
    padding: 1em 0;
    font-size: 1.2em;
    color: #555;
}

.highcharts-data-table th {
    font-weight: 600;
    padding: 0.5em;
}

.highcharts-data-table td,
.highcharts-data-table th,
.highcharts-data-table caption {
    padding: 0.5em;
}

.highcharts-data-table thead tr,
.highcharts-data-table tr:nth-child(even) {
    background: #f8f8f8;
}

.highcharts-data-table tr:hover {
    background: #f1f7ff;
}

JavaScript

function getData(n) {
    const arr = [];
    let i,
        x,
        a,
        b,
        c,
        spike;
    for (
        i = 0, x = Date.UTC(new Date().getUTCFullYear(), 0, 1) - n * 36e5;
        i < n;
        i = i + 1, x = x + 36e5
    ) {
        if (i % 100 === 0) {
            a = 2 * Math.random();
        }
        if (i % 1000 === 0) {
            b = 2 * Math.random();
        }
        if (i % 10000 === 0) {
            c = 2 * Math.random();
        }
        if (i % 50000 === 0) {
            spike = 10;
        } else {
            spike = 0;
        }
        arr.push([
            x,
            2 * Math.sin(i / 100) + a + b + c + spike + Math.random()
        ]);
    }
    return arr;
}
const n = 500000,
    data = getData(n);


console.time('line');
Highcharts.chart('container', {

    chart: {
        zoomType: 'x'
    },

    title: {
        text: 'Highcharts drawing ' + n + ' points'
    },

    subtitle: {
        text: 'Using the Boost module'
    },

    accessibility: {
        screenReaderSection: {
            beforeChartFormat: '<{headingTagName}>{chartTitle}</{headingTagName}><div>{chartSubtitle}</div><div>{chartLongdesc}</div><div>{xAxisDescription}</div><div>{yAxisDescription}</div>'
        }
    },

    tooltip: {
        valueDecimals: 2
    },

    xAxis: {
        type: 'datetime'
    },

    series: [{
        data: data,
        lineWidth: 0.5,
        name: 'Hourly data points'
    }]

});
console.timeEnd('line');