This example displays a choropleth map of the United States, coloring each state based on a numeric diversity value ranging from 0 to 5, with values mapped to a categorical color scale from grey to dark red. The map renders state boundaries using D3’s `d3.geoPath` and TopoJSON data from the US 10m dataset, while state fill colors are assigned via an ordinal `d3.scaleOrdinal`. The code loads the TopoJSON file and appends SVG paths for each state, using the diversity object to set fill colors and adding white state borders.