Logarithmic scale

As explained in Effective Data Analysis

A numerical axis scale in which equal visual intervals represent equal multiplicative ratios.

A logarithmic scale makes equal visual intervals represent equal multiplicative ratios rather than equal additive differences. It helps display values spanning several orders of magnitude, such as population growth, while making exponential change appear linear. section 7.3.2

Use logarithmic scales carefully:

• Prefer them when a linear scale cannot make the full range interpretable. section 7.3.2
• Explain the scale clearly to stakeholders because it can distort perceptions of variation and make trends appear more linear. section 7.3.2

Figure 7.25 Logarithmic scales can help visualize metrics with exponential fluctuations in the data, but they should be used with caution.

Use the figure to compare how logarithmic scaling represents metrics with exponential fluctuations and why cautious interpretation matters. section 7.3.2

How Effective Data Analysis covers it

How deep it goes

Defines the visualization use and interpretation risk, but does not develop mathematical construction or implementation steps.

Examples

Uses population growth and metrics with exponential fluctuations as examples of data suited to logarithmic visualization.

What you can do after

Evaluate/understand when logarithmic scaling improves range visibility and communicate its interpretive limitations responsibly.

How it connects

Connects logarithmic scales with nonlinear scales, linear scales, dual y-axes, and stakeholder interpretation.

liveBookmanning.com

Read Effective Data Analysis on liveBook Get the book at manning.com

Also explained in

• 

  liveBookmanning.com
  Statistics Every Programmer NeedsA logarithmic transformation replaces each value with its logarithm to compress scale differences and reduce positive skewness.
• 

  liveBookmanning.com
  D3.js in Action, Third EditionA logarithmic scale maps values through a logarithmic transformation so multiplicative differences in magnitude can be represented across a visual range.

Compare how 3 books explain logarithmic scale →

Related concepts

• linear scalecontrasts with · A linear scale maps continuous input values to output values through a linear relationship between its domain and range.
• NumPyuses · NumPy is an open-source Python library for numerical computing that provides multidimensional arrays and operations on them.
• scalekind of · A visualization scale maps data values to visual values such as positions, colors, or sizes.
• power-law relationshipused by · A power-law relationship is a mathematical relationship in which one quantity is proportional to another quantity raised to a fixed exponent.
• visualizationused by · Visualization is the representation of data, information, or concepts in visual form to support inspection, interpretation, analysis, or communication.

This explainer was generated by Manning's knowledge graph from the text of Effective Data Analysis. The section links point to the parts of the book it draws on.