geoPath measures
This visualization displays a world map with city populations and interactive country metrics. City markers are sized proportionally to population using a square-root scale, plotted with `geoPath` and `geoNaturalEarth1` projections. Country boundaries come from the World Atlas TopoJSON, with graticules and interiors rendered via D3’s geoPath. Hovering over a country reveals path area, measure, bounding box, and centroid coordinates, computed through `geoGenerator.area`, `bounds`, `centroid`, and `measure` APIs. Data is sourced from the Simplemaps World Cities Database.