This choropleth map visualizes countries colored by their economy classification, using a spectral color scale to differentiate income groups. The visualization displays country names and classifications on hover via tooltips, with a legend showing the ordinal color mapping. Built with D3 v5, the example uses `geoNaturalEarth1` projection and `geoPath` to render world geography from TopoJSON data, while `scaleOrdinal` with `schemeSpectral` assigns colors. The interactive zoom feature uses `zoom`, and a custom `colorLegend` function draws the legend with SVG circles and text.