A choropleth map of global nominal GDP uses color to encode economic values per country. Users click entries in an ordinal color legend to filter the map, dimming countries not belonging to the selected category and highlighting those that do, while a subtle sphere background remains. The map and legend are rendered as SVG, built with D3 v5, using `d3.geoNaturalEarth1` for projection and `d3.geoPath` for drawing countries. Data is loaded from TSV and TopoJSON sources, with the zooming interaction handled via `d3.zoom`.