CipherHealth "Our Hospitals" map - D3
This choropleth map colors U.S. states by a three-tiered value scale (lived, visited, or unvisited) and overlays proportional circles for six cities sized by years resided. Built with D3 v3, it uses the Albers USA projection (`d3.geo.albersUsa`) and `d3.geo.path` to render GeoJSON state boundaries, while assigning fill colors via a linear scale. Hovering a city fades SVG circles and displays a tooltip div, with a legend generated from Bostock’s block.