A choropleth map displays global economic classifications by country, with a color legend encoding each category. Clicking a legend item filters the map, dimming non-matching countries while highlighting the selected group. Hovering reveals country names and values via tooltips. Built with D3 v5, it uses `geoNaturalEarth1` and `geoPath` for SVG map rendering, `scaleOrdinal` with `schemeSpectral` for colors, and `zoom` for panning. Data comes from TopoJSON world-atlas merged with TSV metadata.