This choropleth map colors countries by income group using a natural Earth projection, with a categorical color scale and a clickable legend of colored circles. The map supports zooming and panning via d3.zoom, and country tooltips display name and income group. Built with D3 v5, it uses d3.geoNaturalEarth1 and d3.geoPath to render SVG paths from TopoJSON data loaded from world-atlas, while the legend is implemented as a custom reusable component.