Why using log scale?

What is the function of log scale

Logarithmic scale makes differences of small values more visible vs. diff of large values.

From https://www.mathsisfun.com/definitions/logarithmic-scale.html

When using log scale

From https://www.indeed.com/career-advice/career-development/logarithmic-scale#:~:text=You%20typically%20use%20a%20logarithmic,scales%2C%20from%20farmers%20to%20researchers.

A logarithmic scale shows exponential growth on a graph. It’s a nonlinear scale that’s frequently used for analyzing a large range of quantities compactly. It is extremely useful when graphing a large variance in data.

You typically use a logarithmic scale for two reasons. The first reason is when large values skew the graph of the data, and the second is to show multiplicative factors or percent changes. Many careers use logarithmic scales, from farmers to researchers.

Examples

No Time series

From https://dfrieds.com/data-visualizations/when-use-log-scale.html

  • Raw data

  • Linear scale (small values are smeared)

  • Log scale

Time series

  • Raw data

  • Linear scale (small values smeared, looks like there was no change during the first three years)

  • Log scale (diff between small values receive more weights)