This example presents a choropleth world map visualizing countries colored by income group, with data sourced from World Atlas TopoJSON and TSV files. It uses D3 v5 with a geoNaturalEarth1 projection and d3.geoPath to render countries, while a color legend explains the ordinal color scale. The map supports zooming via d3.zoom, and hovering highlights countries in green. Animated transitions update the legend circles when the scale changes.