Brewing Better Charts and Maps

Frosty P writes: Cindy Brewer chairs the geography program at Penn State, and has devoted much of her career to helping other people make better maps. By bringing research on visual perception to bear on design, she says cartographers can make maps that are more effective and more intuitive to understand. Many of the same lessons apply equally well to other types of data visualization. A big reason people run into trouble with their color schemes, Brewer says, is the way color picking is done in many software programs. Take the RGB cube (or sliders) many programs use to display colors along red, green, and blue axes, for example. 'That's not the least bit perceptually scaled,' Brewer said. 'In some parts of the cube a tiny step gives you a huge perceptual difference. In other parts it all looks the same.' Brewer's best-known invention is a website called Color Brewer, which helps mapmakers pick a color scheme that's well-suited for communicating the particular type of data they're mapping.

Comments

Re:Slashvertising?

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It's so obvious that I encounter the problem in maps, pie charts, categories in video games, etc.

I guess it's not that obvious after all. Add the various degrees of color-blindness that a lot of people have and you end up with a serious issue.

Ed Tufte

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A big reason people run into trouble with their color schemes, Brewer says, is the way color picking is done in many software programs. Take the RGB cube (or sliders) many programs use to display colors along red, green, and blue axes, for example. 'That's not the least bit perceptually scaled,' Brewer said. 'In some parts of the cube a tiny step gives you a huge perceptual difference. In other parts it all looks the same.'

I remember Ed Tufte making the same point about displaying information with rainbow color-maps, an unfortunate favourite of many scientists.