This example visualizes global population data as semi-transparent circles positioned at the geographic centroid of each country on a Natural Earth map. Countries with missing data appear in light red, while the circles’ radii encode 2018 population figures using a square-root scale. The visualization uses d3.geoPath with the geoNaturalEarth1 projection, d3.zoom for panning and scaling, and d3.scaleSqrt for sizing. Data is loaded from a CSV file and a TopoJSON world atlas, processed via topojson.feature, with a custom legend built using d3.scaleSqrt.