The United States of Blooming Risks by University of Wisconsin-Madison

This map is an aggregated visualization of FEMA’s National Risk Index (NRI) for 18 natural hazards.

One of the key design objectives of this map is to explore how, when faced with a large number of attributes, a static map can simultaneously present both the overall spatial pattern and the ability to retrieve individual attribute details. In fact, I had already begun exploring this concept in my previous award-winning map, United States of Natural Disasters (https://cartoguophy.com/maps/us_natural_disaster.html), and gained some valuable experience. In a sense, this map serves as both a "sister piece" and an upgraded version of the earlier work.

The aggregation units for the main map and all inset maps are 1,000-sq-mi hexagons, generated under the Albers equal area conic projection. A specially designed illustrative scale graphic is included on the right side of the map to facilitate easier referencing and measurement.

The values for each hexagon are calculated as the weighted average of the original NRI risk scores at the county level, with weights determined by the proportion of the area each hexagon intersects with the counties. According to FEMA, the risk for a specific hazard is proportional to the Expected Annual Loss from that hazard, adjusted by a community risk factor. This factor increases with high Social Vulnerability and decreases with high Community Resilience. Notably, this map has been revised under the guidance of FEMA personnel.

The multivariate thematic symbol design uses both size and color (lightness) to represent attributes: larger and darker petals indicate higher risks for specific natural hazards.

FEMA does not provide hierarchical structures or categories of the 18 hazards – they are sorted alphabetically. In this floral symbol, all 18 hazard types are arranged along a color spectrum broadly based on their mechanisms. Similar hazards are placed closer together and assigned similar colors that correspond to their categories (e.g., hot/cold meteorological, climatological, hydrological, geophysical), visually revealing potential spatial patterns. Specifically, ChatGPT is used to generate detailed qualitative descriptions for each of the 18 hazards under a consistent standard. These descriptions were then used to create a similarity matrix (18x18), which informed the further sequence construction. The final arrangement of the color spectrum was fine-tuned manually based on my knowledge and expertise, ensuring an accurate and logical progression.

Particularly, the circular 18-color sequence is not a standard RGB color wheel. The segment between red and yellow is intentionally expanded to leverage the human eye’s heightened ability to distinguish orange-like hues. The Hex codes for these 18 colors were generated with the assistance of ChatGPT.

Additionally, small multiple maps of individual hazards are listed on both sides of the main map, aligned with the colors and positions in the petal symbol. At the bottom, an overview map of the averaged risk score is included, supplemented with population density data for additional context.

To sum up, beyond successfully balancing the presentation of overall spatial patterns and individual attribute retrieval, this map intricately combines science (color theory) and art (innovative floral symbol design), theory (multivariate thematic mapping) and application (natural hazard risk assessment), as well as manual craftsmanship (traditional static map design) and automation (AI-assisted processes). It offers both professionals in related fields and the general public inspiring insights from diverse perspectives.

(Data Source: FEMA National Risk Index)