Precinct level maps of US elections are difficult if not impossible to reconstruct. State boards are responsible for providing election data. Precincts are reported simply by a name or location of the polling place often, with errors in names or street locations. These locations must be joined by hand with the Census Bureau's attempts to provide authoritative "Voting Tabulation Districts" (VTDs). States provide data according to their own ballot systems with headers that do not map perfectly well.
A group at Stanford was funded to reconstruct the 2008 election results.
For the 2016 election, precinct level data was reconstructed by a researcher at UCLA and eventually published online by the New York Times.
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