Every line in a sitedia diagram comes from public data. Nothing is drawn by hand and nothing is invented. This page names each dataset, links to it, and says how complete it actually is — including where it is thin.
Two things are worth knowing before the tables. First, ten of the twelve panels work anywhere in the United States because their sources are national. Second, the two that do not — Building age and Building use — depend on county assessor records, which are published city by city. That is why some cities give you twelve panels and others ten.
These render for any US address.
| Panel | Source | Publisher |
|---|---|---|
| Buildings · High-rise · Low-rise · Density | Overture Maps — buildings theme, release 2026-08-19 | Overture Maps Foundation |
| Roads · City block | Overture Maps — transportation theme (city block is derived from the road centrelines, not a separate dataset) | Overture Maps Foundation |
| Green spaces · Water | Overture Maps — base theme (land_use, land,
water) |
Overture Maps Foundation |
| Subway & bus | OpenStreetMap
via Overpass API — railway=station,
station=subway, highway=bus_stop |
OpenStreetMap contributors |
| Terrain · Contours | AWS Terrain Tiles (terrarium), which uses USGS 3DEP over the United States | Amazon Web Services Open Data · USGS |
| Aerial | USGS NAIP imagery (National Agriculture Imagery Program) | USGS / USDA |
Overture is itself a compilation — its building footprints draw on OpenStreetMap, Microsoft and Esri open data. Where a footprint originates in OpenStreetMap it carries the ODbL licence, so if you redistribute a derived database the share-alike term applies. Drawings and images made from it do not trigger that; see Terms.
These two panels come from the assessor of the county or city that publishes them. Each source is a different agency with a different schema, so we join them one at a time.
| City / region | Source | Publisher |
|---|---|---|
| New York City | MapPLUTO
— tax-lot polygons with YearBuilt and LandUse.
How to use it without GIS → |
NYC Department of City Planning |
| Los Angeles County | Assessor parcels — YearBuilt1, UseType |
LA County Office of the Assessor / LA County GIS |
| San Francisco | Assessor Historical Secured Property Tax Rolls joined to the active parcel polygons by block-lot | City and County of San Francisco |
| Seattle / King County | King County tax parcels with YR_BUILT_MAX and
PRES_USE |
King County Assessor · City of Seattle GIS |
| Massachusetts (Boston, Cambridge, Worcester…) | MassGIS
Level 3 Standardized Assessors' Parcels — YEAR_BUILT,
USE_CODE.
How to use it without GIS → |
MassGIS (Commonwealth of Massachusetts) |
| Washington, DC | Common Ownership Lots joined to the CAMA residential, condominium and commercial tables by SSL | DC Office of the Chief Technology Officer · Office of Tax and Revenue |
| Philadelphia | PWD parcels joined to OPA property assessments by BRT number. How the join works → | City of Philadelphia |
| Miami-Dade County | Property boundaries with YEAR_BUILT and DOR_DESC |
Miami-Dade County Property Appraiser |
| Chicago / Cook County | City building footprints (year_built) plus Cook County
Assessor parcel and characteristics extracts |
City of Chicago · Cook County Assessor |
Coverage is not a promise, it is a measurement. The table below is the share of buildings that actually carry a year or a use inside a ½-mile circle on each city's downtown, counted from our own database on 2026-08-27.
| City | Buildings | Year built | Land use |
|---|---|---|---|
| New York (Midtown) | 1,792 | 98.3% | 99.1% |
| San Francisco | 1,183 | 92.2% | 99.7% |
| Boston | 1,355 | 89.3% | 99.9% |
| Philadelphia | 2,378 | 88.4% | 92.3% |
| Los Angeles | 582 | 87.3% | 98.6% |
| Seattle | 566 | 80.6% | 95.1% |
| Washington DC | 700 | 76.7% | 92.0% |
| Miami | 430 | 71.9% | 85.8% |
| Chicago | 661 | 33.1% | 79.7% |
Buildings without a match are drawn in light grey and labelled Unknown. They are not guessed at and not hidden.
Chicago is the weak one, and it is a data problem, not a bug. Cook County publishes parcels as points rather than polygons on the endpoints we can reach, so a parcel record can only be matched to a building when the point lands inside the footprint. On Chicago's long, narrow lots it often lands in the back yard instead. Every city above 85% has parcel polygons. Chicago is listed with ten panels rather than twelve for that reason.
Terrain is relative, not absolute. The elevation tiles are good for reading slope and landform, but they are not a survey. In dense downtowns they sometimes carry bridges, elevated roadways or structures as if they were ground. We remove artefacts narrower than about 80 m, which leaves real hills untouched, but wider ones survive — downtown Miami still reads a few metres higher than it is. Never quote a spot elevation from these diagrams.
Aerial imagery is not live. NAIP is flown on a multi-year cycle by state, so a recently completed building may be missing from the photograph while appearing in the Buildings panel.
Cadastral parcels are drawn for the eight cities above, and nowhere else. They come from the same assessor parcel polygons used for building age and land use, so the panel appears exactly where those do. Outside those cities the panel renders as an empty ground rather than being filled with something approximate.
Zoning and city-planning facilities are still Korea-only. There is no
national equivalent in the United States — zoning is written by each municipality
in its own categories, and getting a legally consequential boundary subtly wrong
is worse than not drawing it. Several of our cities do publish per-parcel zoning
(New York's ZoneDist1, Philadelphia's zoning, Seattle's
ZONING), so this may become a per-city panel later.
If a diagram disagrees with what you know about a site, the fault is usually upstream and worth reporting to the publisher above — but tell us too, using the feedback button on the main page, and we will note it or drop the layer.
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