The emergence of the social sciences / in the nineteenth century / and the ability to work with large datasets / created demand for new ways / of visualizing information.

Processed numerical information / was best expressed / in tables, charts, and graphs.

Mathematics, natural sciences, and social sciences / that employed statistics / were at the forefront / of the development of charts and graphs.

History was a consumer, not a designer, / of most of these new visualizations / — and mostly a sparing consumer at that, / since economic and social history lagged behind political history / as an area of research.

Simple charts and graphs / were not difficult to interpret, / and their visual conventions / became part of / what any ordinary reader would be expected to follow.

As statistical analysis became more sophisticated, / the visualizations that resulted / became more and more central / to the argument.

In some cases, / the visualization made interpretation possible.

These success stories / demonstrated the worth / of statistical analysis and visualization.

Perhaps the most notable example is / John Snow's map of the incidence of cholera / in an 1854 London outbreak, / which helped plot the source of the outbreak / at a single water pump in the neighborhood.

Snow's cholera map / showed that visualizations could serve / as both narrative and analysis.