This choropleth map colors countries by economic classification using a spectral color scale, with hover highlighting and a color legend. It also allows users to zoom and pan the map. The visualization builds on the `world-atlas` dataset (50m TopoJSON and TSV) and renders with D3’s `geoPath` and `geoNaturalEarth1` projection. It employs `scaleOrdinal` and `schemeSpectral` for color mapping, and a custom `colorLegend` function to draw the legend.