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bikepowermodel.fit

Attribution

Physics, maps, weather, elevation, and FIT format work all have fingerprints. This page keeps the credits in one place.

Methods

  • Martin et al. 1998: the cycling power balance, including the bearing-friction term.
  • Blocken et al. 2018 (J. Wind Eng. & Ind. Aerodyn. 179): peloton drag by group size, the anchors behind the drafting model.
  • Monod & Scherrer (critical power) and Skiba (W′-balance recovery kinetics).
  • Heil 2001: frontal-area estimation from height and mass.
  • Defraeye et al. 2010: road-position drag coefficients.
  • Jux, Sciacchitano & Scarano 2023: the wheel sail effect in crosswind and its tire-dependent stall; Barry 2018: yaw-angle probability weighting.
  • Kyle (High-Tech Cycling) and Bertucci et al. 2013: rolling-resistance baselines, cross-checked against bicyclerollingresistance.com's standardized drum tests; cobble Crr cross-checked against MacDermid 2015, Underwood 2011, van Baarle 2022 ride files.
  • Coggan: power-profile tiers, PDC durations, and IF anchors.
  • Chung ("virtual elevation"): the field CdA calibration method behind bpm calibrate.
  • Tatterson 2000 (heat), Wehrlin & Hallén 2006 (altitude), Valenzuela et al. 2022 (durability), Wilson's Bicycling Science (descent cornering limits).

Maps

  • Map data © OpenStreetMap contributors, licensed ODbL. Base tiles are self-built with Planetiler and served as PMTiles; road surface and smoothness tags come from the same data.
  • MapLibre GL JS renders the map (BSD-3-Clause).
  • PMTiles by Protomaps (BSD-3-Clause).

Weather

  • Weather data by Open-Meteo.com (CC-BY 4.0): hourly forecast plus the ERA5-based archive used for past race dates.

Elevation

Elevation is the model's #1 accuracy lever, so it uses national LiDAR terrain models wherever they exist, each under its own open licence (all rehost-OK with attribution). The full roster:

  • Belgium: merged Brussels UrbIS + Digitaal Vlaanderen DHMV + SPW Wallonie Relief (CC0 / free reuse with attribution).
  • France: IGN RGE ALTI 5 m (Licence Ouverte Etalab 2.0).
  • Italy: TINItaly 10 m, INGV (CC-BY 4.0).
  • Netherlands: AHN (CC0).
  • Luxembourg: ACT BD-L-LIDAR 2024 (CC0).
  • Switzerland: swisstopo swissALTI3D (swisstopo OGD / CC-BY).
  • Slovakia: ÚGKK SR DMR 6.0 5 m (CC-BY 4.0).
  • Austria: ALS DGM Österreich, data.gv.at (CC-BY 4.0).
  • Norway: Kartverket DTM via Geonorge (CC-BY 4.0).
  • Finland: NLS KM2/KM10 (CC-BY 4.0).
  • Sweden: Lantmäteriet open elevation (open data).
  • Denmark: DHM via Dataforsyningen (open data).
  • Iceland: LMÍ ÍslandsDEM (open data).
  • Poland: GUGiK NMT (public open data).
  • Germany: per-Land DGM: NRW, Baden-Württemberg, Bayern, Rheinland-Pfalz, Saarland (DL-DE/BY-2.0 or the Land's open licence).
  • Spain: IGN/CNIG MDT05 (CC-BY 4.0, © Instituto Geográfico Nacional).
  • USA: USGS 3DEP (public domain).
  • Canada: NRCan HRDEM (Open Government Licence, Canada).
  • New Zealand: LINZ elevation (CC-BY 4.0).
  • Everywhere else: Copernicus GLO-30 (© European Union, Copernicus programme, produced using ESA/DLR data) with NASA SRTM (public domain) as the final fallback. No holes, only quality differences.

New national sources get their exact licence line added here before they become user-visible.

FIT format

Garmin Power Guide rides on two FIT messages (352 and 353) that were not documented publicly. They were reverse-engineered for this project from binary dumps of Edge-saved files and verified by round-tripping onto a real Edge. The FIT format itself is Garmin's.

Timestamping

Pre-race forecasts are stamped with OpenTimestamps onto the Bitcoin blockchain.

For how the numbers are computed, see Methodology. Licence: MIT; the repo flips public at v1.0.