Choropleth Map with Interactive filtering
This choropleth map displays global economic classifications by country, with an interactive color legend that filters the map to a selected category. Users click legend items to dim non-matching countries and highlight the chosen group, while zooming is supported via d3.zoom. The visualization uses d3.geoNaturalEarth1 projection and d3.geoPath to render world features from TopoJSON data, with d3.scaleOrdinal and d3.schemeSpectral mapping economies to colors. Hover states change country fills to red, and tooltips show country names and values.