This example displays a world choropleth map colored by each country’s economy category, with an interactive legend that filters and highlights selected categories. It uses d3.geoPath and d3.geoNaturalEarth1 for geographic rendering from TopoJSON data loaded via topojson.feature, with d3.scaleOrdinal and schemeSpectral mapping categories to colors. The legend and map respond to clicks, adjusting opacity and stroke widths, while d3.zoom enables panning and zooming.