This example renders a choropleth-style map of United States counties on an SVG canvas. Each county polygon is drawn as a purple path with white strokes, and hovered counties turn red, with the county name appearing as a tooltip. The visualization uses D3 v5’s `geoAlbersUsa` projection with `geoPath` to generate the shapes, and TopoJSON’s `feature` method to parse county boundaries from the us-atlas dataset. County names come from the TopoJSON properties, while the map loads via a remote JSON URL.