Data sources & licences

Every layer comes from a public source under a licence that allows it in the product. This page lists them, with what we never use and why.

Sources in the map today

Source	What we use	Licence	How we credit it
Texas Legislative Council (data.capitol.texas.gov)	Texas VTDs, 2024 general and primary results by VTD, Spanish-surname counts	CC BY 4.0	"Texas Legislative Council" on every precinct card and in Data attribution
MIT Election Data + Science Lab (Harvard Dataverse)	County Presidential Returns 2000–2024; precinct returns 2024	CC0 1.0	"MEDSL (CC0)"
tonmcg/US_County_Level_Election_Results_08-24	County results for seven states	MIT	"tonmcg (MIT)"
VEST (Voting and Election Science Team)	Precinct shapes outside Texas	CC BY 4.0	Per-file credit on each precinct card
U.S. Census Bureau	TIGER/Line boundaries; 2020 PL 94-171 voting-age population	Public domain (17 U.S.C. §105)	Courtesy credit. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.
FCC licence data and Online Public Inspection File	17,522 stations; political-file links	Public domain	Courtesy credit; links go to the FCC
unitedstates/congress-legislators	Members of Congress (names, photos, links)	CC0	Courtesy credit
County elections offices and GIS	Vote centres, precinct and district lines	Public records	Named on each card
County party rosters and calendars	Precinct chairs, officers, events, clubs	As published by the party	Named on each card

How we decide what can ship

Each candidate source is reviewed for grain, coverage, cost, licence and partisan restrictions, then given one of four verdicts:

Ship public: can appear on the open layers, with attribution where required.
Ship gated: only behind a login, under a paid contract, or only for party users within the law's permitted uses.
Reference only: fine for our own research and QA, but not inside the product. We rebuild the layer from the primary source instead.
Never: the licence, a statute or partisan exclusivity forbids it, or the service is gone.

Notable decisions

Source	Verdict	Why
MEDSL precinct returns	Ship public	CC0, including the 2024 President and State precinct files. MEDSL has no shapes, so results are joined to shapes from TLC, VEST or the counties.
VEST precinct results and shapes	Ship public	CC BY 4.0 allows commercial use with attribution.
Texas Legislative Council	Ship public	CC BY, so credit is required on screen.
NYT 2024 precinct map	Reference only	Non-commercial licence. We use it only to check our own joins.
Redistricting Data Hub	Never (in product)	Non-commercial, nonpartisan-only terms.
Dave's Redistricting data	Never	The terms forbid resale.
OpenElections	Reference only	No data licence stated. We pull the official results directly instead.
Vote Smart	Never	The terms prohibit campaign use.
FEC itemised contributions	Never (individuals)	Federal law bars commercial and solicitation use of contributor names (52 U.S.C. §30111(a)(4)).
FEC committee names and addresses	Ship public	The statute expressly allows political committees' names and addresses.
2010 Census surname file	Ship public, aggregated	Used only to compute precinct Spanish-surname shares. Individuals are never labelled.
Google Photorealistic 3D Tiles; Cesium ion	Ship gated	Paid, with no caching. Credits always stay on screen.

Freshness

The political layers are static snapshots, built from the sources above and refreshed when a new release is published. Each card names its source, and where it matters its date (for example the roster date or the election). Election-night scenes use official result feeds from state and county election sites.