This choropleth map colors countries by their economic classification using a spectral color scale, with a hover effect to highlight individual nations and a legend showing the color-to-category mapping. Built with D3 v5, it loads geographic boundaries from a TopoJSON world atlas and income-group data from a TSV file, then projects them using the `geoNaturalEarth1` projection and renders paths with `geoPath`. The visualization implements interactive zooming via the `zoom` event and a custom `colorLegend` component, with the map’s ocean rendered as a styled sphere path.