A choropleth map colors countries by their economic classification using an ordinal color scale with the `schemeSpectral` palette. The visualization uses `d3.geoNaturalEarth1` and `d3.geoPath` to render world geography, with data loaded from the World Atlas TopoJSON and TSV files via `d3.json` and `d3.tsv`. A custom color legend displays the scale, and zooming is enabled through `d3.zoom`. Hovering highlights a country by turning it red.