Data Decimation

This example shows how to use the built-in data decimation to reduce the number of points drawn on the graph for improved performance.

const decimation = { enabled: false, algorithm: 'min-max', };

const decimation = {
  enabled: false,
  algorithm: 'min-max',
};

const NUM_POINTS = 100000; Utils.srand(10); // parseISODate returns a luxon date object to work with in the samples // We will create points every 30s starting from this point in time const start = Utils.parseISODate('2021-04-01T00:00:00Z').toMillis(); const pointData = []; for (let i = 0; i < NUM_POINTS; ++i) { // Most data will be in the range [0, 20) but some rare data will be in the range [0, 100) const max = Math.random() < 0.001 ? 100 : 20; pointData.push({x: start + (i * 30000), y: Utils.rand(0, max)}); } const data = { datasets: [{ borderColor: Utils.CHART_COLORS.red, borderWidth: 1, data: pointData, label: 'Large Dataset', radius: 0, }] };

const NUM_POINTS = 100000;
Utils.srand(10);
// parseISODate returns a luxon date object to work with in the samples
// We will create points every 30s starting from this point in time
const start = Utils.parseISODate('2021-04-01T00:00:00Z').toMillis();
const pointData = [];
for (let i = 0; i < NUM_POINTS; ++i) {
  // Most data will be in the range [0, 20) but some rare data will be in the range [0, 100)
  const max = Math.random() < 0.001 ? 100 : 20;
  pointData.push({x: start + (i * 30000), y: Utils.rand(0, max)});
}
const data = {
  datasets: [{
    borderColor: Utils.CHART_COLORS.red,
    borderWidth: 1,
    data: pointData,
    label: 'Large Dataset',
    radius: 0,
  }]
};

const config = { type: 'line', data: data, options: { // Turn off animations and data parsing for performance animation: false, parsing: false, interaction: { mode: 'nearest', axis: 'x', intersect: false }, plugins: { decimation: decimation, }, scales: { x: { type: 'time', ticks: { source: 'auto', // Disabled rotation for performance maxRotation: 0, autoSkip: true, } } } } };

const config = {
  type: 'line',
  data: data,
  options: {
    // Turn off animations and data parsing for performance
    animation: false,
    parsing: false,
    interaction: {
      mode: 'nearest',
      axis: 'x',
      intersect: false
    },
    plugins: {
      decimation: decimation,
    },
    scales: {
      x: {
        type: 'time',
        ticks: {
          source: 'auto',
          // Disabled rotation for performance
          maxRotation: 0,
          autoSkip: true,
        }
      }
    }
  }
};

const actions = [ { name: 'No decimation (default)', handler(chart) { chart.options.plugins.decimation.enabled = false; chart.update(); } }, { name: 'min-max decimation', handler(chart) { chart.options.plugins.decimation.algorithm = 'min-max'; chart.options.plugins.decimation.enabled = true; chart.update(); }, }, { name: 'LTTB decimation (50 samples)', handler(chart) { chart.options.plugins.decimation.algorithm = 'lttb'; chart.options.plugins.decimation.enabled = true; chart.options.plugins.decimation.samples = 50; chart.update(); } }, { name: 'LTTB decimation (500 samples)', handler(chart) { chart.options.plugins.decimation.algorithm = 'lttb'; chart.options.plugins.decimation.enabled = true; chart.options.plugins.decimation.samples = 500; chart.update(); } } ];

const actions = [
  {
    name: 'No decimation (default)',
    handler(chart) {
      chart.options.plugins.decimation.enabled = false;
      chart.update();
    }
  },
  {
    name: 'min-max decimation',
    handler(chart) {
      chart.options.plugins.decimation.algorithm = 'min-max';
      chart.options.plugins.decimation.enabled = true;
      chart.update();
    },
  },
  {
    name: 'LTTB decimation (50 samples)',
    handler(chart) {
      chart.options.plugins.decimation.algorithm = 'lttb';
      chart.options.plugins.decimation.enabled = true;
      chart.options.plugins.decimation.samples = 50;
      chart.update();
    }
  },
  {
    name: 'LTTB decimation (500 samples)',
    handler(chart) {
      chart.options.plugins.decimation.algorithm = 'lttb';
      chart.options.plugins.decimation.enabled = true;
      chart.options.plugins.decimation.samples = 500;
      chart.update();
    }
  }
];

Docs

• Data Decimation
• Line
• Time Scale