This example displays a choropleth map using 160 countries colored by income group, with a legend and tooltips. It loads world geometry from TopoJSON and joins it with TSV metadata, projecting paths with `d3.geoPath` and a natural Earth projection. The ordinal color scale uses `scaleOrdinal` with `schemeSpectral`, and the legend is built as a custom D3 component. Pan and zoom are enabled via `d3.zoom`, and hovering highlights the selected country in red.