Credits and data

Build notes from the data scripts

Hill list and summit facts

• Source: Database of British and Irish Hills (DoBIH) v18, Munro table munrotab_v8.0.1.csv.
• Link: hills-database.co.uk
• Licence: Creative Commons Attribution 4.0 (CC BY 4.0).
• Attribution: “Contains data from the Database of British and Irish Hills v18 (CC BY 4.0).”
• Fetched: file supplied for the build on 24 October 2026.
• Used for: the 282 current Munros (rows whose 2021 column is MUN), names, DoBIH numbers, heights in metres and feet, grid references, SMC section numbers, RHB sections, OS 1:50,000 and 1:25,000 map sheets, and the classification history for every edition of Munro’s Tables from 1891 to 2021.
• Hill names are as spelled in the DoBIH table, without Gaelic accents. Alternative spellings the table gives in square brackets are kept separately.
• SMC section numbers are shown as numbers only. We could not find an open source for the section names, so none are given.

Summit coordinates

• DoBIH gives OS National Grid (OSGB36) eastings and northings. We convert them to WGS84 latitude and longitude at build time with the Ordnance Survey’s published method: grid to OSGB36 latitude and longitude (Airy 1830 ellipsoid), then a seven parameter Helmert transformation to WGS84.
• The Helmert transformation is accurate to about 5 metres. Checks at build: Ben Nevis lands 5.9 m and Ben Macdui 2.3 m from reference positions.
• Nearest neighbours are straight-line distances between summits, computed by us.

Walking routes (10 pilot Munros)

• Paths and car parks: © OpenStreetMap contributors, available under the Open Database Licence (ODbL). openstreetmap.org/copyright
• Fetched: Overpass API extracts, 24 October 2026.
• Method: each route is the shortest connected line along mapped OpenStreetMap paths, tracks and roads from a mapped car park (amenity=parking) to the summit, computed by us. Busy roads (trunk, primary, secondary) are penalised so the line only uses them where no path exists. Paths graded as alpine (sac_scale) are left out. Where we steer a route through a point, that point is a named OpenStreetMap feature, recorded in the route file. Two routes use one: Ben Lomond through Sron Aonaich, and Ben Macdui through Stob Coire an t-Sneachda.
• Never over open ground: every route must end on the mapped path network within 150 metres of the summit. A route that cannot do that is left out rather than drawn across open ground. All 10 pilot routes passed.
• Car parks with no name in OpenStreetMap are labelled “Car park near” the closest named OpenStreetMap feature, and the distance to it is recorded.
• Routes are one way, car park to summit. Distance, ascent and time are for the way up only.
• These lines are not route descriptions. They show where mapped paths run. Mapped paths can be wrong, missing or out of date.

Elevation

• Source: Copernicus DEM GLO-90 via the Open-Meteo Elevation API.
• Licence: Copernicus DEM © DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018, provided under COPERNICUS by the European Union and ESA; Open-Meteo data CC BY 4.0.
• Fetched: 24 October 2026.
• Method: each route is sampled every 50 metres. Elevations are smoothed with a rolling median of 5 samples (about 250 metres) because the 90 metre DEM steps between cells on paths that cross slopes. Ascent and descent add up rises and falls of at least 5 metres.
• The DEM rounds off summits, so a route’s highest sampled point can sit below the surveyed summit height. Summit heights shown on the site are the DoBIH surveyed figures.

Computed walking time

• Times are computed estimates using Naismith’s rule: 5 km/h plus 10 minutes for every 100 metres of ascent, one way, with no stops. They are not measured times and not a recommendation. Real times vary a lot with fitness, weather, ground and daylight.

Summit conditions

• Source: MET Norway Locationforecast 2.0 (the Norwegian Meteorological Institute), licence CC BY 4.0. Commercial use is allowed with attribution. Fetched under MET Norway’s terms of service: identifying User-Agent, coordinates to 4 decimals, no repeat before the Expires header, If-Modified-Since on repeats, about 7 requests a second at most.
• How: scripts/fetch-conditions.mjs runs once an hour (.github/workflows/conditions.yml, at 17 minutes past) and writes conditions.json for all 282 summits. Pages read that one file, so visitors’ browsers never contact a weather service.
• Variables: air temperature, wind speed and direction, cloud cover, rain or snow over the next hour and the weather symbol, for the forecast hour that covers the fetch time. altitude= is set to the summit height, so MET Norway adjusts the temperature to the summit. These are model forecasts, not observations.
• Worked out on the site, not from MET Norway: wind chill (Environment Canada / US National Weather Service formula, shown at or below 10°C), the freezing level (summit height plus summit temperature divided by the standard 6.5°C per 1,000 m lapse rate, so a rough guide that is wrong in temperature inversions), and sunrise and sunset (NOAA solar equations).
• Saved fallback: each page embeds its summit’s figures from the file present when the site was built, dated and labelled out of date, for when the hourly file can’t load.
• Mountain forecast link: each peak links to the Mountain Weather Information Service forecast for its area (West Highlands, Northwest Highlands, Cairngorms and Monadhliath, or Southeastern Highlands). Areas are assigned in src/lib/mwis.ts from MWIS’s own area descriptions (read 25 Oct 2026); where the areas overlap, the choice is a judgement. In winter, the Scottish Avalanche Information Service as well.

Walking routes for the other Munros (built automatically, 24 Oct 2026)

• Script: scripts/build-all-routes.mjs (inputs from scripts/fetch-route-areas.mjs and scripts/get-dem.sh).
• Paths and car parks: OpenStreetMap via Overpass, 16 area extracts (ODbL).
• Start: the public car park with the quickest mapped-path route to the summit, costed like Naismith (each metre climbed counts as 8.3 m of walking). On the 10 hand-picked routes it chose the same car park 8 times, and the other two were alternative standard starts (Achintee for Ben Nevis; a lay-by 48 m away at Altnafeadh).
• Heights: Copernicus DEM GLO-30, AWS Open Data registry, decoded locally (scripts/dem-to-npy.py).
• Review: every route carries auto: true and flags. The review list is ROUTE-REVIEW.md, made from data/route-review.json.
• Not built: Munros with no mapped path within 250 m of the summit, or no public car park joined to it, get no route. A line is never drawn over unmapped ground; a gap of up to 250 m at the summit is flagged and not drawn.

Getting there

• Source: OpenStreetMap via the Overpass API (scripts/build-access.mjs, fetched 25 Oct 2026), ODbL: railway stations and halts, bus stops, and public car parks (amenity=parking, not private or customers-only).
• Parking: the walking route’s own start where there is a route; otherwise the nearest public car park to the summit, which is not necessarily the usual start.
• Station and bus stop: the nearest to that car park, as the crow flies. A mapped bus stop says nothing about the timetable, so the page links Traveline Scotland and Google Maps public transport directions.
• Known gap: OpenStreetMap does not say whether a car park can be reached by public road. Corrour (Sgòr Gaibhre, Carn Dearg) is a station with no public road, but shows a car park.

Gaelic names, meanings and stories

• Source: each Munro’s English Wikipedia article (CC BY-SA 4.0) and its Wikidata Gaelic label (CC0), matched by DoBIH number (Wikidata P6515). Fetched 25 Oct 2026 by scripts/fetch-wiki.mjs; 249 of 282 have article text (summits without their own article use the parent hill’s).
• Method: short facts put into our own words from the article only (data/names/part-*.json), then checked by scripts/merge-names.mjs: a Gaelic form must match Wikidata or appear in the article; an IPA pronunciation must appear in the article (the simple respelling is derived from it); meanings and stories need a source article. Result src/data/names.json: 279 Gaelic forms, 128 meanings, 10 pronunciations, 224 stories.

Big days

• Script: scripts/build-big-days.mjs → src/data/bigdays.json. Ridge links: Munros within 4.5 km with no more than 300 m drop below the lower summit on the straight line (Copernicus GLO-30). Days start on our routes, follow ridge links, and return the same way or down another Munro’s route plus the road (1.3 × straight line, at most 10 km), within 10 hours by Naismith. Days with scrambling (route flags, or the Skye Cuillin) show no time.

Offline and GPX

• GPX files (/routes/<slug>.gpx) are generated from the route data at build time. “Save for offline” caches the route page, its scripts, the weather files and map tiles (Sentinel-2 cloudless z8 to z15, Terrarium terrain z8 to z14, OpenFreeMap paths z12 to z14) around the route in the browser; public/sw.js serves them with no signal.

Route starts, round 2 (25 Oct 2026)

• Public roads only: a car park counts as a start only if it is within 200 m of a road joined to the public network (unclassified or bigger, or service roads that connect to one and are not private). Estate road networks with no public way in, such as Corrour’s, do not count.
• Stations: railway stations can be starts, costed 15% higher than driving, so they win only where the train is clearly the way in (Corrour).
• Usual starts from Wikipedia: for 113 Munros the article names where walkers usually start (data/start-hints.json, place plus quote, with a grid reference where given). The builder prefers a public car park within 3 km of that place when it is joined to the summit by mapped paths and no more than 40% costlier than the best start.

Munro Tops

• The 226 Tops (2021 column “TOP” in the DoBIH Munro table, CC BY 4.0), matched to their Munro by the name before ” - ”, else the nearest Munro (scripts/build-tops.mjs → src/data/tops.json). Shown on peak pages and as small circles on the map from zoom 10.

Daylight through the year

• Sunrise to sunset on the 15th of each month at the summit, NOAA solar equations (src/lib/sun.ts). Stag stalking season: 1 July to 20 October (the open season for red deer stags in Scotland).