This example displays a world map colored by each country's economy classification, with a color legend showing the categorical scale. The visualization uses d3.geoNaturalEarth1 projection and d3.geoPath to render the map from TopoJSON data loaded via topojson, while d3.scaleOrdinal with schemeSpectral assigns colors to economic categories. The map supports zooming through d3.zoom, and hovering highlights individual countries in red. A custom colorLegend component renders the legend as SVG circles with text labels, and the sphere background is filled with blue.