Custom axis labels for log transformation

Hi TzuChiao26 

I ran into a challenge with a scatter plot in Power BI where both axes were log-transformed using something like 

LOG10([Volume CP] + 1). The goal was to handle zeros and negative values gracefully while still making the data distribution readable especially when there are extreme values.

But here’s the catch: the axis labels ended up being 0, 1, 2, 3… which makes sense mathematically, but not to business users. They don’t think in logs they think in actual volumes like 10, 100, 1000.

So here’s how I tackled it:

• I kept the log transformation for the axis values. This kept the chart clean and helped with outliers and skewed data.

• Then I created a simple mapping table:

  • 0 → 0
  • 10 → 1
  • 100 → 2
  • 1000 → 3

  Just two columns Orginal Value  and Log value.

• In the scatter chart, I added reference lines at log values 0, 1, 2, 3 and labeled them as 0, 10, 100, 1000. This way, the chart still uses the log scale, but the labels feel familiar and intuitive to stakeholders.

• As a bonus, I added tooltips to show the actual [volume cp] value when users hover over a point. So even though the axis is log-scaled, they still see the real-world number.

It’s not a perfect solution Power BI doesn’t let us override axis labels directly but this approach made the chart much more digestible for non-technical users. And honestly, it saved me from having to explain what “log scale” means in every meeting.

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Regards,
Akhil.