Edmund Halley (1656 - 1742)

Most known for his eponymous comet, Halley developed the use of contour lines on maps to express different atmospheric conditions.

William Playfair (1759 - 1823)

The inventor of line and bar charts. Generally considered the father of statistical graphics.

Charles de Fourcroy (1766 - 1824)

A French director of fortifications, Fourcroy published an influential essay on engineering and construction. The following table from that work graphically compares the growth of European cities and is consider a precursor to today's treemaps.

Charles Joseph Minard (1781 - 1870)

A French civil engineer, Minard's most famous visualization was of Napoleon's 1812 Russian campaign. Showing great levels of detail in a map, he highlighted the dramatic loss in the French troops. Jam packed and very interesting!

John Snow (1813 - 1858)

As a London physician in 1854, he started mapping cholera deaths and identified the cause of the epidemic as being a water pump in the area. His work was retold in the third season (2019) of the TV series Victoria.

Florence Nightingale (1820 - 1910)

In addition to her work as a nurse in the Crimean War, she used data visualization to help describe the need for better hospital conditions. She created the rose diagram.

Luigi Perozzo (1856–1916)

The first person to introduce 3D representations of data.

Otto Neurath (1882 - 1942)

An Austrian sociologist and political economist, Neurath was the inventor of ISOTYPE visualizations which used pictorial representations to display concepts and connections (think precursors of traffic signs). He is also known for his stark pictographic interpretations of statistics of pre- and post- world wars.

ISOTYPE 'The Great War' by Otto Neurath. In ISOTYPE — International System of TYpographic Picture Education. L.A. Worrell. http://www.laworrell.com/blog/tag/Pictograms.

John Wilder Tukey (1915-2000)

Tukey was an American mathematician who is best know for the development of the Fast Fournier Transform algorithm and naming the "bit." His 1958 paper also contained the earliest known use of the term "software."  He was also the inventor of the box plot in 1977.