Using Transparency in R to Improve Clarity

When you plot a lot of data at once, points and lines can obscure others and hide patterns. Transparency can help reveal what is really there.

Transparency doesn’t seem to be used much, but it’s as easy to set as color. All you have to do is append a value from 0 to 99 to a hexadecimal color code. A value of zero gives you completely transparent whereas a higher value gives you more opaque. For example, if you add “05” to “#000000” so that it’s “#00000005” you have a transparent shade of black.

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About the Author

Nathan Yau is a statistician who works primarily with visualization. He earned his PhD in statistics from UCLA, is the author of two best-selling books — Data Points and Visualize This — and runs FlowingData. Introvert. Likes food. Likes beer.