Population Density by World Cities
This visualization uses a contour map to show population density across the world, based on the populations of large cities. It overlays political borders and labels for major cities, and supports panning and zooming. The implementation leverages `d3.geoNaturalEarth1` projection, `d3.geoPath`, and `d3.contourDensity` to generate density contours, which are colored using a custom scale combining CubeHelix and Reds. City labels are placed without overlap using the RBush spatial index, and the map is rendered with SVG and the `d3.select` API.
AI-generated descriptionA contour map visualization of population density across the world, estimated based on populations of large cities. Features panning & zooming, and a label placement algorithm that uses an R-Tree spatial index to avoid overlaps.