A world choropleth map colors countries by economic classification, using a spectral ordinal color scale. Users can click any country to highlight it and dim all others, or click again to clear the selection; clicking legend swatches filters the map to a specific category. The visualization uses d3.geoNaturalEarth1 with d3.geoPath to render TopoJSON country outlines from the world-atlas dataset, d3.scaleOrdinal for coloring, and d3.zoom for panning and scaling. An SVG legend, built with custom functions, adds interactive filtering and selection feedback.