Data sources & licences
Everything on OpenFell either comes from an open dataset or is computed from a published formula. This page lists every source, what we do with it, its licence and the attribution we owe — the long form of the credits in the site footer.
| Source | What we use it for | Licence | Attribution required |
|---|---|---|---|
| Database of British & Irish Hills v18.3 | The backbone of every peak page: hill names and alternative names, height in metres and feet, drop (prominence), col grid reference and height, six- and ten-figure grid references, hill classifications, county and DoBIH region, and OS 1:50,000 and 1:25,000 sheet numbers. | CC BY 4.0 | Yes |
| ONS Open Geography Portal | Country boundaries (December 2023) and GB National Park boundaries (December 2022). Used to decide which jurisdiction's access law applies to a summit, and which national park — if any — it stands in. | Open Government Licence v3.0; contains OS data © Crown copyright and database right 2023 | Yes |
| OpenStreetMap | Every long-distance path: the route line itself, plus the name, waymark symbol, managing operator, endpoints and official website recorded on the route relation. Distances, day stages, country and national-park crossings, coastal share and nearby summits are all measured by us from that line — they are not OpenStreetMap values. | ODbL 1.0 — share-alike | Yes — plus share-alike on derived data, see below |
| MET Norway Locationforecast 2.0 | Live summit weather on peak pages, requested for the summit's coordinates and altitude so the forecast is altitude-adjusted rather than a valley reading. Served through our own edge proxy and cached about 30 minutes. | CC BY 4.0 | Yes |
| Wikipedia (English) | Background context on peak pages — geology, etymology, ridge and route character, first ascents — and on the car-free station pages. Articles are matched to hills and stations by coordinate proximity rather than by name alone, so a fell is never confused with a town that shares its name. Heights, prominence, grid references and passenger figures never come from Wikipedia; those stay with DoBIH, NaPTAN and the ORR. | CC BY-SA 4.0 | Yes — each page links the article it drew on |
| Wikimedia Commons | Summit and station photographs. We only publish images under a licence permitting commercial reuse — public domain, CC0, CC BY or CC BY-SA. Non-commercial and no-derivatives images are filtered out automatically and never appear here. | Per image — stated in the caption | Yes — photographer and licence in every caption |
| Official trail designations | Marking which long-distance paths are National Trails (the 16 statutory routes of England and Wales) and which are NatureScot's 29 Scotland's Great Trails. These are administrative designations, not OpenStreetMap tags, so they come from a checked name list rather than from the route data. | Facts of public administration — no licence attaches | No |
| Computed astronomy | Sunrise, sunset and civil twilight times for the daylight planner and peak pages, from the NOAA solar equations implemented in-house. | None required — computed values | No |
| Coordinate conversion (OSGB36 ↔ WGS84) | Grid references to and from latitude and longitude, for the grid-reference tool and for plotting summits. Airy 1830 ellipsoid, Transverse Mercator projection and a seven-parameter Helmert transform, implemented in-house from published geodetic formulae. | None required — computed values | No |
| National Landscape, NSA and AONB boundaries | The designated-landscapes section: England's National Landscapes from Natural England, Wales's AONBs from Natural Resources Wales via DataMapWales, Scotland's National Scenic Areas from the Scottish Government's spatial data portal, and Northern Ireland's AONBs from DAERA via OpenDataNI. Used only to decide which designated landscape, if any, a summit stands in. | Open Government Licence v3.0(all four); the England, Wales and Scotland layers contain OS data © Crown copyright and database right | Yes |
| Environment Agency real-time flood-monitoring API and SEPA time-series data service | The river-levels tool: gauge locations, latest river levels and (EA only) typical ranges, fetched live in your browser. This uses Environment Agency flood and river level data from the real-time data API (Beta). Scottish data provided by SEPA. Wales and Northern Ireland publish no comparable open API, and the tool says so rather than pretending coverage. | Open Government Licence v3.0 | Yes |
| MOD firing notices via GOV.UK | The firing-ranges page: which training areas affect open country, the flag and lamp conventions, and the public information lines — links verified August 2026. Live firing schedules are published by the MOD, not reproduced by OpenFell. | Open Government Licence v3.0 | Yes |
| postcodes.io (ONS Postcode Directory) | Postcode positions for the grid-reference converter, queried live in your browser — nothing is stored. | Open Government Licence v3.0; contains OS data © Crown copyright and database right, and Royal Mail data © Royal Mail copyright and database right | Yes |
| NaPTAN (Department for Transport) | Railway-station names, localities and OS coordinates for the car-free station pages and the by-train section on peak pages. Every hill–station distance and bearing is computed from these coordinates. | Open Government Licence v3.0 | Yes |
| ORR estimates of station usage | The station's CRS code, operator and annual entries-and-exits estimate shown on each station page. Doubles as the test of what counts as a National Rail station: NaPTAN's rail area also lists heritage railways, and only stations the ORR knows are published here. | Open Government Licence v3.0 | Yes |
| Food Standards Agency Food Hygiene Rating Scheme, plus Food Standards Scotland's separate Food Hygiene Information Scheme | The "Get food nearby" section on peak pages: up to 3 rated places to eat within 10 km of the summit. We only show business types that can plausibly serve a walk-in customer (restaurants, cafés, pubs, takeaways, and hotels/inns whose own name reads as a public house), and drop records whose name reads as institutional — a school kitchen or a corporate canteen carries a food hygiene rating too, and is not a place to eat. That filter is necessarily imperfect; each listing links to its official rating page to check. | Open Government Licence v3.0 | Yes |
Indicative regional climate figures (src/data/climate.ts) | The best-month tool only. Compiled from public Met Office regional climate summaries; rounded and smoothed so areas compare like for like, marked indicative wherever shown, and pending verification. | Compiled figures — marked indicative | Attribution to be finalised alongside the figures |
Our attribution strings
These are the credits we carry, verbatim. Reuse them if you reuse our pages.
Contains data from the Database of British and Irish Hills v18.3, licensed under CC BY 4.0.
Source: Office for National Statistics licensed under the Open Government Licence v.3.0. Contains OS data © Crown copyright and database right 2023.
Weather data from MET Norway, licensed under CC BY 4.0.
Trail route data © OpenStreetMap contributors, available under the Open Database Licence (ODbL).
The site footer carries a condensed form of the same four credits on every page.
Our obligations under the ODbL
OpenStreetMap is the one source here with a share-alike condition, so it deserves spelling out rather than burying in a table cell. Our trail dataset is a Derivative Database of OpenStreetMap, and we accept the consequences that follow:
- Attribution. Every page carries "© OpenStreetMap contributors" in the footer, and each route page links the specific OpenStreetMap relations it was built from.
- Share-alike. The measurements we derive — distances, stage splits, crossings, summit proximity — are offered under the ODbL on the same terms, not claimed as proprietary.
- No technological restriction. The route geometry is served as plain static files; nothing here is locked behind a login, a paywall or DRM. The whole derived route set is downloadable as trails-overview.json.
The access checker and the peak pages contain no OpenStreetMap data and are unaffected — the share-alike condition attaches to the trail dataset, not to the site as a whole.
How often each source is refreshed
- Hill data — reviewed quarterly, and rebuilt whenever the Database of British & Irish Hills issues a new release.
- Trail routes — re-harvested from OpenStreetMap periodically; mapping there changes continually, so a route re-measured today may differ slightly from the figure shown.
- Boundaries — rebuilt when the ONS publishes a revised country or national-park boundary release.
- Weather — fetched live from MET Norway and cached roughly 30 minutes at the edge, so a forecast may be up to half an hour old.
- Stations — NaPTAN positions and the ORR usage estimates are refreshed when the ORR publishes its annual station-usage release; each station page states the data period its passenger figure covers.
- Access-rights pages — reviewed when the law changes; each page shows the date it was last reviewed.
- Computed values — sun times, grid conversions and walking-time estimates are calculated on demand; there is nothing to refresh.
How the pipeline works
A build script reads the DoBIH CSV and keeps only hills carrying at least one of nine classifications — Munro, Corbett, Graham, Donald, Wainwright, Wainwright Outlying Fell, Hewitt, Nuttall or historic county top — dropping anything outside the UK, so Isle of Man, Channel Islands and Republic of Ireland hills do not appear. Each surviving hill is then tested point-in-polygon against the ONS country and national-park boundaries to establish its jurisdiction and its park, and neighbouring summits are found by great-circle distance. The same boundary files are trimmed to four decimal places of coordinate precision and published as static JSON, which is what lets the access checker answer entirely inside your browser.
The trail pipeline is separate. It pulls every OpenStreetMap relation tagged as a walking route on an international, national or regional network across Britain and Ireland, resolves the ones that are split across several relations back into single routes, then stitches each route's ways end to end and measures the result. Routes are kept only if at least 60% of the line falls inside the UK — with a three-kilometre tolerance, because the ONS coastline is generalised and a clifftop path otherwise reads as being at sea — and only if they reach 30 km. Everything else on a route page is computed from the stitched line. No elevation source covers these routes, so no ascent figure is published for them.
Current county and unitary-authority tops (DoBIH's CoU flag) are deliberately excluded as an entry criterion: small unitary authorities would promote urban parks to "summits". A hill that qualifies on any of the nine criteria above still displays itsCoU status if it holds one.
What we do not use
- No Ordnance Survey premium or derived data. We build only on open data. The only OS-originated content on the site is what the ONS lawfully includes in its open boundary products, credited above. OS sheet numbers come from DoBIH and are references, not OS mapping.
- No content scraped from other hiking sites or apps. No route descriptions, no summit logs, no user reviews and no trail ratings lifted from anyone else. That is a deliberate limit rather than an oversight: review text belongs to the people who wrote it, the collections are protected by database right, and the UK text-and-data-mining exception covers non-commercial research only. Where we would otherwise quote someone else's opinion of a hill, we link to them instead.
- No invented trip reports. Nothing on this site describes a walk that did not happen. First-hand notes appear only for hills the editor has actually been on, and are labelled as a personal account — see who writes this.
- No user-uploaded content. There are no accounts, comments or uploads. TheGPX analyser runs entirely in your browser: the file is read locally and nothing is uploaded to us or to anyone else.
Corrections
If a figure here is wrong — a height, a grid reference, a licence notice, a park assignment, an attribution we have got the wrong way round — please tell us and we will correct it. While the site is in preview the contact address hello@openfell.example is a placeholder and does not receive mail; a working address will be published here and on theabout page.