This visualization displays a choropleth map of countries colored by economic classification, with an interactive color legend that filters highlighted regions. The map uses the Mercator projection through `d3.geoMercator` and renders geographic paths via `d3.geoPath`. Users can click legend circles to highlight matching countries, which are drawn using a categorical `scaleOrdinal` with the `schemeSpectral` color range. Data comes from a CSV file joined with TopoJSON world atlas features, and the entire SVG view supports pan and zoom through `d3.zoom`.