Let's Make a map
This example displays a zoomable world map using geographic data from the world-atlas TopoJSON files. It renders country boundaries as SVG paths via d3.geoPath with a d3.geoNaturalEarth1 projection, and d3.zoom enables pan/zoom interactions that update the map group’s transform. Country names come from a TSV file joined by ISO numeric codes, appearing as hover tooltips via SVG title elements. Countries fill red on hover, while the sphere outline is drawn from a GeoJSON sphere object.