Sources & data layers — districtry San Francisco

This app is a reader over other people's data. It draws no boundary of its own and names no officeholder it cannot cite, so the useful question about any answer it gives is who published this, and when. That is what this page is for: the publishers the app credits as a whole, then one row per layer naming the source behind that layer specifically.

Not for legal or official use. Boundary and roster data come from public sources that explicitly disclaim legal precision. Always confirm district assignments and officeholders with the relevant government office before relying on them for anything official.

Data last verified: July 18, 2026

Where a source publishes nothing, the app says so rather than guessing — the missing-data panel on the map is the standing list of what nobody publishes yet, and what would close each gap.

Who publishes the data

The upstream publishers this app depends on, across all layers. Per-layer provenance is in the matrix below.

DataSF The city's own open-data portal — supervisor districts, police districts, analysis neighborhoods, attendance areas, precincts, and the facility points behind the nearest-station layers.
U.S. Census Bureau (TIGERweb) Congressional and California legislative district geometry, and ZIP Code Tabulation Areas.
OpenStreetMap contributors (Nominatim & Photon/Komoot) Address search and the office-address pins.
unitedstates/congress-legislators The U.S. House roster joined to the congressional district card.
OpenStates California Senate and Assembly members and their district offices.
BART Board of Directors districts and the directors who hold them.
SFUSD Enrollment guidance linked from the attendance-area card, which is what decides a placement.
San Francisco Department of Elections Polling places and the early-voting sites transcribed per election.
USGS The National Map Post office locations.

The layer matrix

16 layers — 7 political and legislative, 3 public safety, 2 schools, 4 geography and amenities. Each row names the publisher the boundary comes from, where the names on the card come from, and the ground the layer actually answers on — outside that ground the layer hides itself rather than guessing.

Political & legislative 7 layers

Districts that elect somebody — from your ward to your seat in Congress.

Layer	What it answers	Boundary source	Who it names	Where it applies
U.S. House District`congress`	Which U.S. House district covers this address, and who represents it.	Congressional districts from the U.S. Census Bureau's TIGERweb Legislative service, clipped to San Francisco and shipped with the app	Members come from the unitedstates/congress-legislators dataset, refreshed weekly and reviewed before it ships.	San Francisco.
California State Senate District`ca-senate`	Which California State Senate district covers this address, and who holds the seat.	California Senate districts from the U.S. Census Bureau's TIGERweb Legislative service, clipped to San Francisco and shipped with the app	Senators come from the OpenStates bulk people export, refreshed weekly and reviewed before it ships.	San Francisco.
California State Assembly District`ca-assembly`	Which California State Assembly district covers this address, and who holds the seat.	California Assembly districts from the U.S. Census Bureau's TIGERweb Legislative service, clipped to San Francisco and shipped with the app	Assemblymembers come from the OpenStates bulk people export, refreshed weekly and reviewed before it ships.	San Francisco.
BART Director District`bart-director`	Which BART Board of Directors district covers this address, and who represents it.	BART district boundaries as BART publishes them to ArcGIS Online	Directors ship with the app from BART's own board roster; the card links the board rather than inferring a name.	San Francisco — the districts themselves cross city and county lines.
Election Precinct`election-precinct`	Which voting precinct this address is in.	Voting precincts published by the Department of Elections on DataSF (jg6x-23ig)	No roster: a precinct has no officeholder. The card links the city's polling-place lookup.	San Francisco.
Supervisor District`supervisor-district`	Which Board of Supervisors district covers this address, and who represents it.	Current Supervisor Districts from DataSF (hcgx-vtsb), simplified and shipped with the app	Supervisors are rebuilt weekly from the same DataSF dataset and reviewed before they ship. The volatile name field is stripped from the shipped geometry, so a decadal boundary can never freeze an officeholder.	San Francisco.
Voting Center & Ballot Drop-off`early-voting`	The nearest early-voting sites to this point for the current election.	Early-voting sites transcribed per election from the Department of Elections and shipped with the app	No roster: a voting site has no officeholder. Hours change per election — the card links the Department of Elections, which is the only current authority on them.	San Francisco.

Public safety 3 layers

Who answers a call at this address, and where they answer it from.

Layer	What it answers	Boundary source	Who it names	Where it applies
Police District`police-district`	Which SFPD district covers this address, and which station serves it.	Current Police Districts from DataSF (d4vc-q76h), simplified and shipped with the app	No roster is joined; the card links SFPD's own station directory rather than naming officers.	San Francisco.
Police Station`police-station`	The nearest SFPD stations to this point, by straight-line distance.	City facility points on DataSF (rwdu-9wb2), filtered to police stations	No roster is joined; the card gives the station and its address.	San Francisco.
Fire Station`fire-station`	The nearest fire stations to this point, by straight-line distance.	City facility points on DataSF (nc68-ngbr), filtered to Fire Department stations	No roster is joined; the card gives the station and its address.	San Francisco.

Schools 2 layers

The district, the attendance zone, and the schools nearest the point.

Layer	What it answers	Boundary source	Who it names	Where it applies
Elementary Attendance Area`elementary-attendance-area`	Which SFUSD elementary attendance area this address falls in.	Elementary attendance areas published on DataSF (e6tr-sxwg)	No roster; the card links SFUSD's enrollment guidance, which is what decides a placement.	San Francisco.
School Location`school-site`	The nearest school sites to this point, by straight-line distance.	School sites published on DataSF (7e7j-59qk)	No roster is joined; the card names the school and its address.	San Francisco.

Geography & amenities 4 layers

The boundaries that place an address without electing anyone, plus the nearest public services.

Layer	What it answers	Boundary source	Who it names	Where it applies
ZIP Code`zip-code`	Which ZIP Code Tabulation Area contains this address.	ZCTAs from the U.S. Census Bureau's TIGERweb service	No roster: a ZIP code has no officeholder.	San Francisco.
Neighborhood`neighborhood`	Which of the city's analysis neighborhoods contains this address.	Analysis Neighborhoods from DataSF (j2bu-swwd), simplified and shipped with the app	No roster: a neighborhood has no officeholder. These are the boundaries the city uses for planning and statistics, which are not always the name a listing or a local would use.	San Francisco.
Post Office`post-office`	The nearest post offices to this point, by straight-line distance.	USGS National Map structures service, queried within the metro bounding box	No roster is joined; the card names the facility and its address.	San Francisco.
Library`library`	The nearest public libraries to this point, by straight-line distance.	City facility points on DataSF (fhhu-wqa7), filtered to the Public Library department	No roster is joined; the card names the branch and its address.	San Francisco.