Vertical mass is parasitic on the infrastructure that surrounds it.
This view overlays four layers on a chosen city’s central business district: the CBD polygon (sketched or center-plus-radius fallback); transit stations within roughly twelve kilometres of the city centroid; Amtrak stations within twenty-five kilometres; and the telecom POP / IXP / MMR footprint that anchors the metro’s peering and hyperscale traffic.
Drawn as an orange polygon if geo.cbd_boundaries contains a sketch for the chosen city; otherwise as an orange circle approximating the center-plus-radius footprint from cities.cbd_boundaries. Polygons are aspirational sketches, not legal CBD designations.
Heavy-rail, light-rail, BRT, intercity bus terminals within ~12 km of the city centroid, from transport.transit_stations. Popup carries operator, lines served, daily ridership, and whether the station is a transfer or intermodal hub.
Long-distance intercity passenger rail terminals from transport.amtrak_stations. The 490-station network covers all states with service.
Points-of-presence, internet exchange points, and meet-me rooms from infrastructure.telecom_nodes. The peering footprint a CBD’s hyperscale traffic depends on.
Transit-station spatial join uses ST_DWithin on cities.cities.geom at ~0.12° (roughly 12 km) — wider than most legal CBD definitions to capture commuter ingress. Telecom nodes are matched by city name (the table carries no geometry), so multi-city metros may under-count. Transit-score and walk-score are from cities.cities (Walk Score / ACS).