This visualization presents a world map where individual countries are colored according to an ordinal income or economy classification. Users can click any country to select it, which highlights that country while dimming all others; clicking again deselects it. A color legend on the left allows filtering the map by a specific income group, similarly dimming non-matching countries. The map uses a natural Earth projection rendered as SVG paths via `d3.geoPath`, with zooming handled by `d3.zoom`. Data is loaded from the World Atlas TopoJSON and TSV files, and the color scale uses `d3.scaleOrdinal` with the spectral scheme.