This choropleth map visualizes world economies by color-coding countries according to their economic classification. Users can click legend categories to filter the map, highlighting matching countries while dimming others; clicking again resets the filter. The map uses d3.geoNaturalEarth1 projection and d3.geoPath for rendering, while d3.scaleOrdinal with d3.schemeSpectral supplies the color scale. Data comes from the world-atlas dataset, loaded via d3.tsv and topojson.feature.