This choropleth map colors world countries by economic classification using a d3 ordinal color scale with the spectral scheme. The visualization employs d3.geoNaturalEarth1 projection with d3.geoPath to render TopoJSON features, while a custom colorLegend module displays the ordinal scale through SVG circles and text. Users can pan and zoom via d3.zoom, and hovering highlights countries in red through CSS. Data is merged from a TSV file and world-atlas TopoJSON using d3.tsv and d3.json.