This choropleth map colors world countries by economic classification, using a spectral color scale to distinguish categories. Clicking a legend item filters the map to highlight only matching countries, while zooming and panning are enabled via d3.zoom. The visualization imports world-atlas TopoJSON and TSV data, projecting features with d3.geoNaturalEarth1 and d3.geoPath. Map and legend are rendered as SVG, with hover states and opacity dimming for non-selected regions.