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How to Detect the Distortions of Maps

All maps have biases. A new online exhibit explores the history of map distortions, from intentional propaganda to basic data literacy.
A map of population density in Tokyo, circa 1926, shows how maps splice and dice demographic data.
A map of population density in Tokyo, circa 1926, shows how maps splice and dice demographic data.Leventhal Map Center, Boston Public Library
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This interview is adapted from the latest edition of MapLab, CityLab’s biweekly newsletter about maps that reveal and shape our urban spaces. Sign up for the newsletter here.

Every map is infused with its maker’s decisions, which ultimately present a pattern, story or argument. Sometimes those choices of design, labeling, data selection, and data slicing show up as obvious biases, as in the case of Donald Trump’s infamously augmented 2019 map of Hurricane Dorian. More often, though, this inherent “truthiness” flies under the radar of a map’s tidy, matter-of-fact visual presentation, as in the many maps and models being made now of semi-reliable Covid-19 case data.