This choropleth map visually encodes countries by economy group using a spectral color scale. Hovering over legend items interactively filters the map, dimming countries outside the selected category while highlighting the chosen group. The visualization uses `d3.geoPath` and `geoNaturalEarth1` for map projections. Data is loaded from the world-atlas TopoJSON and TSV sources, with legend interactions managed through D3 selections and event handlers.