Choropleth Map with Interactive Filtering
This choropleth map displays global income groups using a natural Earth projection, with countries colored by income classification. Clicking a color legend item filters the map to highlight only countries in that group, dimming all others and adjusting the sphere’s opacity. Hovering reveals country names and values via SVG titles. Built with d3.geoPath, d3.zoom, and d3.scaleOrdinal, it loads TopoJSON and TSV data from the world-atlas package, with interactive legend selection managed through d3 event handlers.