[Math] What are examples of legitimate usage of logarithmic scale when drawing a chart

logarithms

Quite often a chart is drawn using logarithmic scale for one axis (usually the the y-axis). This is often used for abuse when presenting information – logarithmic scale alters greatly how the values are plotted on the plane.

Still I guess there are legitimate cases when using logarithmic scale for one axis which represents a value which is linear in nature (not earthquake magnitude which is already logarithmic itself).

What are examples of such legitimate cases where using logarithmic scale allows for better analysis of plotted data?

Best Answer

On a log scale a relationship of the form $x \mapsto x^{\alpha}$ shows up as a straight line (of slope $\alpha$) when you plot $\log x^{\alpha}$ against $\log x$. This is useful with many data sets such as frequency responses in engineering, as you can easily estimate constants just by looking at their graph.

See Darrell Huff's 1954 classic "How to Lie with Statistics" for nice examples of misleading scales.