Bundled neighborhood polygons — provenance & license

These per-city GeoJSON files give the annotation resolver real neighborhood boundaries for places OSM tags as label-nodes-only (Chinatown, the Marina, the Mission, …), instead of a flaky live-Overpass lookup or a synthesized buffer disc. Looked up by point-in-polygon + name (see src/data/neighborhoodPolygons.js).

Provenance

san-francisco.json

• Downloaded from: https://data.sfgov.org/resource/j2bu-swwd.geojson?$limit=100 (HTTP 200, 1,713,909 bytes, retrieved 2026-07-30). The catalog page is the "Analysis Neighborhoods" map view p5b7-5n3h, which is backed by dataset j2bu-swwd (columns the_geom, nhood); the legacy api/geospatial/p5b7-5n3h?method=export endpoint no longer serves the geometry after DataSF's November 2023 map-format migration.
• License evidence: the dataset metadata (https://data.sfgov.org/api/views/j2bu-swwd.json, and identically on p5b7-5n3h) declares "licenseId": "PDDL" / "license": {"name": "Open Data Commons Public Domain Dedication and License", "termsLink": "http://opendatacommons.org/licenses/pddl/1.0/"}. Public domain — fully compatible with this repo's public release.
• Content: all 41 Analysis Neighborhoods, created by SF DPH and the Mayor's Office of Housing and Community Development (with the Planning Department) from groupings of 2010 Census tracts. Dataset last updated upstream 2023-10-17.
• Transform: scripts/build-sf-neighborhoods.mjs (deterministic; re-run it against the raw download to reproduce the bundled file byte-for-byte):
  1. properties.nhood → properties.name — names kept verbatim, no renames or aliasing.
  2. Douglas-Peucker simplification per ring, tolerance 2e-5° (~2 m) — trims hyper-detailed shoreline vertices without visibly moving boundaries (42,667 → 9,150 vertices).
  3. Coordinates rounded to 6 decimals (~0.1 m), consecutive duplicates dropped, rings re-closed.
  4. Single-part MultiPolygons collapsed to Polygon; features sorted by name.

File format

FeatureCollection with city + features[], each { properties: { name }, geometry: Polygon|MultiPolygon }, coordinates [lon, lat] rounded to 6 decimals. The lookup module is source-agnostic — to add or swap a city, drop in a file with this shape and register it in CITY_FILES in src/data/neighborhoodPolygons.js.