This choropleth map visualizes global economic classifications by coloring each country according to its income group. Built with D3 v5 and TopoJSON, it uses an ordinal color scale with the spectral scheme and renders geographic shapes via `d3.geoPath` with a natural Earth projection. The map supports pan and zoom through D3’s zoom behavior, and hovering highlights countries in red. A custom legend, generated with appended SVG circles and text, displays the color categories, while data is loaded from the World Atlas TopoJSON and TSV files.