The United States of Natural Disasters

By Atlas Guo, University of Wisconsin-Madison

This map offers an innovative and comprehensive visualization of seven natural disasters in the U.S., enabling readers to gain insights from both an overview and a spatial-semantic perspective.

The most striking feature is the multivariate symbol design. To evenly distribute space for multiple visual elements, hexagonal units are used—balancing functionality and aesthetics. Each hexagon is divided into seven segments, each assigned a distinct hue along the color wheel. Lightness (HSL) or value (HSV) is carefully controlled to minimize perceptual interference between hues.

While there’s no perfect way to arrange seven disaster types around the color wheel, efforts were made to enhance intuitive associations: e.g. red for wildfire, yellow for drought, and blue for hurricanes; flood is placed at the bottom, while earthquake is centered to reflect its origin.

The design draws inspiration from halftone printing effects and pointillism painting. Like those techniques, the colored dots form a coherent image from a distance, while retaining individual detail up close. Through extensive print testing, a configuration of partially overlapping circles was developed, striking a balance between overall legibility and variable-specific clarity.

In addition to hue, each segment’s opacity varies—ranging from full to half—based on FEMA disaster declaration counts. Population density is conveyed through varying shades along hexagon edges. To support further exploration and enhance accessibility for colorblind readers, small multiples of univariate maps are included on the left.

The hexagonal statistical units (1,000 sq miles each) were generated using an Albers Equal-Area projection, with specific computational strategies applied during variable aggregation.

More information about this map could be found at https://cartoguophy.com/maps/us_natural_disaster.html.