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Data licence & sources

Last updated: 22 July 2026

This page is the reference for where our trail route lines come from, what licence each one carries, and — for the routes we derive from OpenStreetMap — exactly how they are produced. It exists so that anyone can check our attribution, reproduce our routes, or reuse them under the same terms we received them.

1. Route geometry from OpenStreetMap

A growing share of the routes on DirtbagMaps is derived from OpenStreetMap. Those routes are © OpenStreetMap contributors and are available under the Open Database License 1.0 (ODbL).

Every affected trail carries that credit in three places: on the trail page itself, inside the <metadata> and <copyright> blocks of every GPX file you download from us, and in the credits list on our About page. The naming of a route is ours; the geometry is OpenStreetMap's.

How the routes are produced

ODbL §4.6 lets a publisher describe the method by which a Derivative Database was created rather than distribute the derived database itself. This is that description, and it is deliberately specific enough to reproduce:

  1. We identify the OpenStreetMap route relation for the trail (type=route, route=hiking|foot) and record its relation ID.
  2. We fetch that relation's member ways through the Overpass API, recursing into type=superroute children where a long trail is modelled as stages, and de-duplicating ways that appear in more than one child.
  3. We drop non-path member roles (approach, alternative and marker members) and stitch the remaining ways into a single ordered chain by repeatedly joining the nearest matching endpoints.
  4. We sample elevation for the chain from public terrain models — SRTM where it is available, and Mapzen/ASTER GDEM above 59°N, because SRTM's coverage stops at 60°N. Elevation is interpolated back onto the full-resolution geometry so distance is never lost to simplification.
  5. We apply quality gates and reject the result rather than publish a bad one: a relation with gaps that would have to be bridged by straight lines is refused, as is a derived length that departs materially from the trail's documented length, or an elevation series with too many missing samples. A refused trail keeps whatever route it already had and is queued for manual work.
  6. We write a GPX file whose metadata names the source relation, credits OpenStreetMap contributors, and states the ODbL.

No editorial content is derived from OpenStreetMap by this process — only the line on the map. Our stage plans, difficulty ratings, gear lists, climate summaries and written guides are our own work and are not part of any Derivative Database.

Getting the data

The GPX for any OpenStreetMap-derived trail is downloadable from that trail's page, and what you receive is the derived route under the ODbL — you may redistribute and adapt it under that licence, including commercially, provided you keep the attribution and share alike. If you want the underlying data instead, it is all upstream: the relation ID in each file's metadata resolves at openstreetmap.org/relation/<id>. If anything here is unclear or you need a route in another form, email rr@rtrosenberg.dk and we will send it.

2. Routes from other sources

Not every trail is OpenStreetMap-derived yet. Where a route came from somewhere else, the trail page says so, and the licence of that source governs it rather than the ODbL — a route is never labelled as OpenStreetMap-derived unless it actually is, and our GPX files never claim authorship of geometry we did not produce.

We are actively migrating the remainder onto openly licensed sources. Where no open source exists for a trail, we would rather not carry the trail than carry a route we cannot license.

3. Base maps, terrain and other data

4. Trail names and waymarking

Some trail names and waymarking systems are registered trademarks of the federations that maintain them — for example GR and GR 20 are registered marks of the Fédération française de la randonnée pédestre. We use such names only to identify the trail being described. DirtbagMaps is not affiliated with, endorsed by, or a licensee of any of these federations, and we do not reproduce their waymarking graphics as our own branding. See our About page for the full notice.

5. Licence conflicts

Where our Terms of Service conflict with an open licence covering a given dataset, the open licence prevails for that dataset. We cannot and do not attempt to use our Terms to reduce rights that ODbL, CC BY or any similar licence grants you.

6. Corrections

If you believe a route on DirtbagMaps is misattributed, carries the wrong licence, or reproduces material it should not, email rr@rtrosenberg.dk. We would rather fix or remove a route quickly than argue about it — tell us which trail and what the problem is, and we will act.