A choropleth-style map of Brooklyn library branches uses orange points over a green base map. Each point is plotted by longitude and latitude from BPL_Locations.csv, projected with `d3.geoMercator()` and drawn as SVG circles. Hovering a point displays a tooltip with the branch name, phone number, and accessibility tags. The underlying neighborhood boundaries come from Brooklyn GeoJSON, rendered through `d3.geoPath()`.