Downloads

Every OTC release, newest first, with what changed and its files. The list is read from the release index on the data host, so it shows each release as soon as it is published.

Releases

The release list is read from OTC_index.json.

Each release lists the changes that matter to a user of the data: stations added or removed, stations whose recommended constant set changed, stations whose M2 phase or amplitude moved, the upstream source versions, and any change of format_version. The full per-station list is in the release files.

Formats

The files in every release and what each one holds

Every release has one stem, OTC_{YYYYMMDD}, where the date is the UTC day the release was built. A second release on the same day gets a counter: OTC_{YYYYMMDD}.2.

Files in a release
File	Contents
`OTC_{YYYYMMDD}.json`	Primary format. One document with every station, its constant sets, constituents, offsets, conventions, validation and provenance.
`OTC_{YYYYMMDD}.json.gz`	The same file, gzip-compressed.
`OTC_{YYYYMMDD}.jsonl`	One station document per line, for streaming and for clean per-station diffs between releases.
`OTC_{YYYYMMDD}.meta.json`	The release document without `stations`: release metadata, conventions, licences and the constituent table. A `.jsonl` reader needs it.
`OTC_{YYYYMMDD}.jsonl.gz`	Optional. The `.jsonl` file, gzip-compressed. A release is complete without it.
`OTC_{YYYYMMDD}.csv`	One long table for spreadsheets, with a `record_type` column (`station`, `constant_set`, `constituent`, `offset`, `convention`, `validation`, `tombstone`). Columns that do not apply to a row type are empty. RFC 4180 quoting, UTF-8, LF line endings.
`OTC_{YYYYMMDD}.parquet`	Optional. The CSV table, typed and compressed, for analysts. A release is complete without it.
`OTC_{YYYYMMDD}.sha256`	SHA-256 checksums of every file in the release, in `sha256sum` format.

Locations

Where the files are hosted, the latest pointers and the archive

Files: https://data.opentideconstants.org/OTC_{YYYYMMDD}.{ext}, served from Cloudflare R2. Every release stays available, and a dated file is never overwritten.
Latest pointer: https://data.opentideconstants.org/OTC_latest.json is a small manifest, not a data file. It gives the current release date, its format_version, its DOI, and the URL, size and SHA-256 of each file. It is updated only after every file of a release is uploaded and verified. Read it first, then download the dated files.
Latest pointer per format major: https://data.opentideconstants.org/OTC_latest-f{MAJOR}.json (for example OTC_latest-f0.json) has the same fields for the newest release of that format_version major. A reader that supports only an older major keeps getting updates after a new major comes out.
Release index: https://data.opentideconstants.org/OTC_index.json lists every release, newest first, with the same fields as the pointer.
Browsers: the data host allows cross-origin GET and HEAD from any site, so a web page can read the files directly.
Archive: the same public files are deposited at Zenodo with a DOI for each release. See How to cite.

Check a download with:

sha256sum -c OTC_{YYYYMMDD}.sha256 --ignore-missing