Radar with Log Axis throws error

[zifix]

Version

4.3.0

Steps to reproduce

1. Set up a radar chart
2. Add to options:

   radiusAxis: {
      type: 'log'
    }
   

What is expected?

The same chart to render with log10-axis

What is actually happening?

Got an exception:

ERROR TypeError: "radiusAxis is null"
    render RadiusAxisView.js:61
    renderComponents echarts.js:1369
    each util.js:298
    renderComponents echarts.js:1367
    render echarts.js:1353
    update echarts.js:805
    setOption echarts.js:398

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[Ovilia]

radiusAxis is for bar/line charts in polar system, which is not for radar charts. We do not support log axis for radar axis (actually, there is no such thing as radar axis).

If you do need such a feature, I can set this issue to be a feature request. You are encouraged to making a pull request for this feature, and we can give you some advice on how to implement if you are interested in it.

[zifix]

Hi @Ovilia,
thanks for the clarification. I think the feature can be useful and I'm proficient in javascript, a total noob at charts though as you can see in my mix-up of the terminology 👅
If you think that's good enough to handle the complexity of this feature, then I'm willing to give it shot.
BR
Zifix

[Ovilia]

@zifix Great!
@100pah Please give some advice on how to make this possible.

[pissang]

Hi @zifix, really appreciate your passion!

In ECharts, axis type like 'log' is abstracted as Scale. There are different kinds of scales:

• Ordinal
• Interval
• Log
• Time

Ordinal scale and interval scale are the most commonly used. Ordinal is for category data, while the interval is for the number like data.

We fixed the scale to be interval in the radar chart. https://github.com/apache/incubator-echarts/blob/master/src/coord/radar/Radar.js#L43 But as you mentioned. It's better to support log scale.

About how to create the scale from the given option. https://github.com/apache/incubator-echarts/blob/master/src/coord/axisHelper.js#L248 may be an example you can reference.

Please let us know if you have any more questions. Looking forward to your fix:)

[zifix]

@pissang Not sure if it was as easy as I think it was, but you are surely going to tell me :P