DOCUMENTS AND DATA

The dataset

Speed limits and road geometry for the whole planet, built from OpenStreetMap and packaged into regional files the app downloads once and then reads offline.

It lists every file, its size, its SHA-256 checksum and which countries it covers. File names include a hash of their contents and therefore change between releases, so the manifest is the only reliable index — a direct file URL will eventually stop resolving.

Files are served from https://maps.motosema.com/ and need no key or account.

The format is documented in SPEC-001: a header, a directory of independently decodable blocks, then delta-encoded varints. It is deliberately simple to read — a few hundred lines in any language — because a format only we can parse would not be much of a publication.

Licence

The data is © OpenStreetMap contributors, available under the Open Database License 1.0.

Our files are a derivative database, so they carry the same licence. You may copy, distribute, adapt and build on them, commercially or otherwise, provided you attribute OpenStreetMap and share any derived database under ODbL in turn.

We are not the source of this data. Every road and every limit in it was surveyed and entered by an OpenStreetMap contributor. What we contribute is the packaging: extracting the roads that carry limits, resolving the units, cutting the planet into pieces a phone can hold, and fixing the mistakes described below.

The build pipeline

The tools that produce the dataset are published as an archive, so anyone can rebuild it from raw OpenStreetMap rather than take our word for the output.

It consumes Geofabrik regional extracts, uses Natural Earth boundaries to decide which country each region belongs to, and runs on an ordinary desktop — there is no cluster and no cloud build. A full planet run takes hours, not days.

Geofabrik require no credit for their extracts, which are OpenStreetMap data rather than their own work. We name them anyway, because a pipeline that hid where its input came from would be no use to anyone trying to reproduce it.

Corrections

Building this surfaced several defects — some in our own handling, some in assumptions that anyone doing the same work would likely make. They are written up in full because each one produced plausible wrong output rather than an error, which is the kind that survives review.

Getting in touch

Questions about the data, the format or the licence: info@motosema.com

If you find an error in a speed limit, the fix belongs in OpenStreetMap rather than with us — we rebuild from it monthly, so a correction there reaches every MotoSema rider within weeks.