# Days Used time-zone boundary data

This download contains the machine-readable time-zone boundary data bundled with Days Used, along with its format decoder and generator sources. Download the file at [`packages/geo_resolver/assets/time_zones.bin`](packages/geo_resolver/assets/time_zones.bin); `manifest.json` lists the files and their SHA-256 hashes.

© OpenStreetMap contributors. This data is derived from [timezone-boundary-builder 2026e](https://github.com/evansiroky/timezone-boundary-builder/releases/tag/2026e), specifically `timezones-1970.geojson.zip` (SHA-256 `3de9301809f44d0ac5ca902b40835d85d9980a35497f0ffda293e98955dc3fb7`). The derived data is offered under the [Open Database License 1.0](https://opendatacommons.org/licenses/odbl/1-0/). The complete license text is supplied as `ODbL-1.0.part1.txt` followed immediately by `ODbL-1.0.part2.txt`.

The generator also uses IANA tzdb `zone1970.tab` (observed SHA-256 `5f23781702bf51408ff1581daa109ab3b9257fb433b1554e579d92172892c0cf`; [IANA tzdb](https://data.iana.org/time-zones/tzdb/)). It selects zones for countries with multiple offsets in its data window, simplifies rings at 1,000 metres and removes polygons approximately 1 km² or smaller. The decoder documents the little-endian GRB1 representation. See the included generator for the exact algorithm.

The generator expects the unzipped `combined-1970.json`, `zone1970.tab`, Dart and the original `geo_resolver` package context, including its `jurisdiction_log` dependency and the timezone package. This extract alone is not a dependency-complete standalone build. With those inputs and dependencies available, the original command is:

```sh
dart run tool/build_time_zones.dart --geojson /path/to/combined-1970.json --zone1970 /path/to/zone1970.tab
```

The bundled data is provided as-is. The source files and license texts are included for attribution and examination; reproduction has not been independently verified from this extract.