This example renders a choropleth map of the United States using D3’s geo APIs. It employs `d3.geoAlbersUsa` for the projection, `d3.geoPath` to draw state boundaries, and `d3.geoGraticule` to overlay a graticule and outline. State geometries come from a TopoJSON source, converted to GeoJSON via `topojson-client`’s `feature` function. The visualization uses a join-based workflow to create SVG paths, with a white stroke separating states and a light gray graticule.