This interactive map viewer displays world countries, U.S. states, and U.S. counties, letting the user switch between geographic scales via buttons. It renders dynamic SVG paths using React's `useState` and `useEffect` hooks, fetching GeoJSON from `us-atlas` and `world-atlas` via TopoJSON. The visualization applies distinct projections—`geoNaturalEarth1` for the world map and `geoAlbersUsa` for U.S. views—through `d3.geoPath`, with a deep blue background. Map features are drawn as white-filled, black-stroked paths, providing a clean comparison of administrative boundaries across scales.