Smoothed line series

This tutorial looks at what options we have to create smoothed line and area series.

Creating smoothed line series

amCharts 5 offers types of smoothed line series:

Class	Comment
am5xy.SmoothedXLineSeries	Used for horizontal series.
am5xy.SmoothedYLineSeries	Used for vertical series.
am5xy.SmoothedXYLineSeries	Used for scenarios where series does not have any specific direct, e.g. scatter chart.

Using proper axis type ensures that the line itself will not go outside its value bounds.

let series = chart.series.push(
  am5xy.SmoothedXLineSeries.new(root, {
    name: "Series",
    xAxis: xAxis,
    yAxis: yAxis,
    valueYField: "value",
    valueXField: "date"
  })
);

var series = chart.series.push(
  am5xy.SmoothedXLineSeries.new(root, {
    name: "Series",
    xAxis: xAxis,
    yAxis: yAxis,
    valueYField: "value",
    valueXField: "date"
  })
);

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See the Pen
Monotone series by amCharts team (@amcharts)
on CodePen.0

Line tension

Smoothed lines do have one setting: tension.

It's a numeric value from 0 (zero) to 1 (one) indicating strength the two connected points are "pulling" at the connecting line.

The smaller the number, the more lose and curvy the line will be. 1 indicates maximum strength which means it will be a perfectly straight line.

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Configuring appearance

By all intents and purposes all smoothed line series types are essentially a line series. Its appearance, just like line series, is configured via strokes.template and fills.template.

For more information, please refer to "Line series: Configuring appearance" tutorial.

Using D3 smoothing

If the three smoothed line series choices does not fit our requirements, we have an option of using various smoothing algorithms bundled with d3-shape library.

Since those are not bundled with amCharts, you may need to load load them as modules from d3-shape npm package or compiled JS binaries from some CDN:

import * as d3 from "https://cdn.skypack.dev/d3-shape@3";

<script src="https://cdn.jsdelivr.net/npm/d3-shape@3"></script>

Then it's just as easy as setting curveFactory on your regular LineSeries:

let series = chart.series.push(
  am5xy.LineSeries.new(root, {
    name: "Series",
    xAxis: xAxis,
    yAxis: yAxis,
    valueYField: "value",
    valueXField: "date",
    curveFactory: d3.curveBumpX
  })
);

var series = chart.series.push(
  am5xy.LineSeries.new(root, {
    name: "Series",
    xAxis: xAxis,
    yAxis: yAxis,
    valueYField: "value",
    valueXField: "date",
    curveFactory: d3.curveBumpX
  })
);

See the Pen
amCharts 5: Using d3 curve factories by amCharts team (@amcharts)
on CodePen.0