This choropleth map colors countries by economic classification, with a hover effect highlighting individual nations and a legend showing the categorical color scale. The visualization renders world geography using `d3.geoPath` with a Natural Earth projection, while `d3.zoom` enables pan and zoom interaction. Data loads from the world-atlas TopoJSON and TSV files, merged by country ID, and the color scale uses `d3.scaleOrdinal` with `schemeSpectral` ranges. The legend is built as a reusable component with `selection.enter` and `merge` patterns.