This fork of a choropleth map colors countries by their income group using a spectral color scale. The visualization employs the d3 geoNaturalEarth1 projection and d3.geoPath to render geographic features from world-atlas TopoJSON and TSV data. A custom color legend displays the ordinal scale, while the d3 zoom event enables interactive panning and zooming. Hovering over a country turns it red and reveals its name and income category in a tooltip.