How to Map with Contour Lines and GeoTIFF in R
GeoTIFF data can provide high granularity but make it hard to see patterns when data is sparse. Contour lines provide an aggregated view that makes patterns easier to see.
GeoTIFF is a metadata standard that attaches geographic information with a TIFF file, which is an image file format. The fun part is that the pixels encode the data. For example, the Cropland Data Layer from the United States Department of Agriculture is an estimate where crops grow, based on satellite imagery. The map below shows land used to grow winter wheat:
I love subtlety, but more contrast and contour lines can help you see the patterns more clearly. In this tutorial, you’ll learn how to make such lines and adjust for your own maps.
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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.
