Any way to increase the chart plot curve interpolation?

sungkhum · December 13, 2020, 6:55am

I’m trying to smooth out my chart line, and while curveBasis is a step in the right direction, it barely smooths the chart out with the data I am using. Is there anyway to manually increase the amount it smooths out the data in the Perspective Time Series Chart?

I’d like it to look more like this:

https://docs.inductiveautomation.com/display/DOC80/Perspective+-+Time+Series+Chart

github.com

d3/d3-shape/blob/main/README.md#Curves

# d3-shape

Visualizations typically consist of discrete graphical marks, such as [symbols](#symbols), [arcs](#arcs), [lines](#lines) and [areas](#areas). While the rectangles of a bar chart may be easy enough to generate directly using [SVG](http://www.w3.org/TR/SVG/paths.html#PathData) or [Canvas](http://www.w3.org/TR/2dcontext/#canvaspathmethods), other shapes are complex, such as rounded annular sectors and centripetal Catmull–Rom splines. This module provides a variety of shape generators for your convenience.

As with other aspects of D3, these shapes are driven by data: each shape generator exposes accessors that control how the input data are mapped to a visual representation. For example, you might define a line generator for a time series by [scaling](https://github.com/d3/d3-scale) fields of your data to fit the chart:

```js
const line = d3.line()
    .x(d => x(d.date))
    .y(d => y(d.value));
```

This line generator can then be used to compute the `d` attribute of an SVG path element:

```js
path.datum(data).attr("d", line);
```

Or you can use it to render to a Canvas 2D context:

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pturmel · December 13, 2020, 1:43pm

Perspective’s architecture doesn’t allow you to plug in any old javascript you want. You’ll need to use the ideas portal to convince IA to add the functionality in a future version, or use the SDK to create your own charting component with the features you desire.

Or use the java math libraries Ignition offers to generate the curve yourself and supply the high-resolution set of points to the existing chart.

sungkhum · December 13, 2020, 4:35pm

I think I figured out a way - changing the point count to a very low number for the tag history as the series data:

And then adding a plot and changing the interpolation: