This choropleth map colors countries by their economic classification using a spectral color scale, with an interactive legend that filters the map by clicking a category value. The visualization uses d3.geoNaturalEarth1 and d3.geoPath to project and draw the geographic features, while d3.zoom enables panning and zooming on the SVG canvas. The legend, built with custom D3 selections, dims unselected categories and allows toggling filters. Country data comes from the world-atlas TopoJSON dataset, enriched with economic metadata from a TSV file.