ziptz
Copyright (c) 2026 cho

Distributed on PyPI as "ziptz-us" and imported as "ziptz"; the Go module is
github.com/choey/ziptz. All three name this one library, so a licence audit
that finds this file under ziptz_us-*.dist-info/ is looking at the right thing.

The source code in this repository is licensed under the MIT License; see
LICENSE.

This file records where the generated lookup tables in ziptz.go and ziptz.py
come from, and the attribution their sources ask for. It travels with the
source and with any distribution of it.

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ZIP code centroids
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US Census Bureau ZCTA Gazetteer file (2024).

A work of the United States Government, and so not subject to copyright
protection in the United States (17 U.S.C. Sec. 105). No conditions attach.

    https://www.census.gov/geographies/reference-files/time-series/geo/
    gazetteer-files.html

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Time zone boundaries
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timezone-boundary-builder, by Evan Siroky, whose boundaries derive from
OpenStreetMap. Made available under the Open Database License (ODbL) v1.0.

    https://github.com/evansiroky/timezone-boundary-builder
    https://opendatacommons.org/licenses/odbl/1-0/

Reached at generation time through timezonefinder, a development-only
dependency that is neither imported by this library nor shipped with it.

    https://github.com/jannikmi/timezonefinder

Attribution, as ODbL Sec. 4.3 asks for:

    Contains information from timezone-boundary-builder, which is made
    available under the Open Database License (ODbL), and from OpenStreetMap,
    (c) OpenStreetMap contributors.

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What the tables are
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The tables are not a copy or a redistribution of the boundary data. They were
produced by taking public-domain Census ZCTA centroids and asking, for each
one, which zone it falls in -- then reducing 33,791 answers to 157 run-length
range records over 3-digit prefixes plus 233 individually named exceptions,
about 1.3 KB in total. They carry no geometry: no boundary, coordinate, or
shape from the source survives in them, and the source cannot be reconstructed
from them.

This is recorded as an aggregate rather than a substantial extract of the
source database -- a Produced Work in ODbL's terms rather than a Derivative
Database -- which is why the code is offered under a permissive licence with
the attribution above carried alongside.

Anyone redistributing this library should keep this file with it. Anyone whose
own use makes that characterisation matter to them should read the ODbL and
reach their own conclusion rather than relying on this note.
