This example shows a choropleth map of the world, coloring each country according to its economy category using an ordinal color scale. The map renders with SVG paths generated by d3.geoPath and a Natural Earth projection, and it supports zooming and panning through d3.zoom. A custom color legend is built with circles and text labels. Data is loaded from world-atlas TopoJSON and TSV files, processed with topojson.feature, and the color scale uses d3.scaleOrdinal with schemeSpectral.