This interactive choropleth map colors countries by income group, with a color legend that animates its circles and uses sequential reds from d3.scaleOrdinal. Built with d3.v5 and topojson, it projects world atlas data using d3.geoNaturalEarth1 and renders countries as SVG paths via d3.geoPath. A zoom tool from d3.zoom is applied, and hover effects highlight individual countries, while data is loaded from unpkg-hosted TSV and TopoJSON files.