This example shows a choropleth map of world countries colored by economic classification, with an interactive color legend and zoom-and-pan navigation. The visualization uses d3.geoPath with the Natural Earth projection to render country boundaries from TopoJSON data loaded from the world-atlas package, while d3.scaleOrdinal with the Spectral color scheme maps economy categories to fill colors. Users can zoom and pan the map via d3.zoom, and hovering highlights individual countries in red. A custom color legend, built with reusable D3 selections, displays color swatches and labels in an SVG overlay.