A choropleth map displays world countries colored by economic classification, with an interactive legend that filters which countries remain highlighted. Users click legend categories to isolate specific economic groups, dimming non-matching countries to 10% opacity. The visualization uses d3.geoNaturalEarth1 and d3.geoPath for map projection, d3.zoom for panning, and a d3.scaleOrdinal with schemeSpectral for coloring. Data combines TopoJSON world geometry with TSV metadata from the world-atlas package. The SVG rendering supports hover effects and a legend built with custom SVG groups and circles.