This choropleth map shows global economies by income group, with a color legend that filters countries by category. The map renders world geography using d3.geoPath with a Natural Earth projection, while a d3.scaleOrdinal with a spectral scheme assigns colors. Clicking a legend entry dims non-matching countries and highlights the selected group, using D3 v5’s zoom behavior for panning. The visualization loads TopoJSON and TSV data from the World Atlas package and draws everything as SVG.