This D3 choropleth map visualizes countries colored by their economy category, using a spectral color scale. Users can click legend items to filter the map, highlighting matching countries while dimming others. The map supports zooming and panning through the `d3.zoom` event. It uses `d3.geoPath` and the `geoNaturalEarth1` projection to render geographic features, and the `d3.scaleOrdinal` color scale with `d3.schemeSpectral` for encoding. Data is loaded from the World Atlas topojson and TSV files, processed with TopoJSON.