LIVING SURVEY — measurements are reviewed continuously as new data and local evidence arrive. Seen a sign, a gate, or a better name? Submit an update no account needed · photos welcome via GitHub

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Chemin de l'Adret

2251.8 m · net rise 240.5 m · total ascent 241.2 m · overall 10.7% · evidence quality B (good) · Les Thuiles · Alpes-de-Haute-Provence ·

Shape: sustained — 30% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 260 m.

Found purely from mapping and LiDAR data, and not yet matched against books, race records or lists — it may be well known to locals under a name we've never heard. It was cross-checked against IGN’s BD TOPO® road network, OpenStreetMap and the classified LiDAR HD point cloud, but a discovery can still be an artifact of the terrain model or the map. Treat it as a well-evidenced hypothesis until someone has ridden it. If you know this road, tell us what you found — photographs, corrections and local knowledge all welcome; the map links below let you scout it first.

≈ Overhead cover (tree canopy or structures) spans 8% of this route — detected by comparing the surface model (DSM, treetops and rooftops) against the terrain model (DTM, bare ground). Under cover the bare-ground model is built from fewer laser returns, so metre-scale readings can wobble; maxima whose window sits in a covered zone are marked ≈ below — less certain — the flag does not say whether the true value is higher or lower. Longer windows average over more clean ground and are steadier.

Gradient ladder what do windows mean?

WindowMaximumLocated at
2 m (diagnostic)≈28%737–739 munder overhead cover terrain reads 60.5% at 971–973 m across a structure — excluded
3 m (diagnostic)≈25%736–739 munder overhead cover terrain reads 54.4% at 970–973 m across a structure — excluded
5 m≈22%736–741 munder overhead cover terrain reads 45.4% at 970–975 m across a structure — excluded
10 m≈19%734–744 munder overhead cover terrain reads 31.8% at 970–980 m across a structure — excluded
20 m≈17.3%726–746 munder overhead cover terrain reads 24.2% at 970–990 m across a structure — excluded
25 m≈16.9%289–314 munder overhead cover terrain reads 22.2% at 969–994 m across a structure — excluded
50 m≈16.4%297–347 munder overhead cover terrain reads 17.3% at 944–994 m across a structure — excluded
100 m15.8%274–374 m

may start earlier Extent detection suggests reviewing where this climb starts/ends.

Map

Check this route yourself: Google Maps route via their router · Street View at the base where coverage exists · geojson.io our exact measured line · OpenTopoMap

This climb's data: OCL JSON — the full gradient ladder, quality flags and provenance in the OpenClimb Ladder format.

Surface: paved (4% unpaved), according to BD TOPO®, IGN's national topographic database: paved for the first 2,162 m; unpaved from 2,162 m to the top. The steepest 25 m lies on the paved part.

Measured, not vetted. This page records what the laser record shows about the road's shape — nothing more. Nobody has necessarily ridden or inspected this road for the survey, and a page here is not a recommendation and no guarantee that the road is open, surfaced, rideable or safe. Gates, private sections, missing rights of way and hazards do not show up in elevation data. Check access and conditions on the ground and make your own judgment.

Ridden it, or know better? Submit data for this climb no account needed ·

Route colour = gradient over a 25 m window: <10% 10–20% 20–25% ≥25%

  © OpenStreetMap contributors · topo tiles © OpenTopoMap (CC-BY-SA) · vector tiles OpenFreeMap · aerial imagery © IGN, BD ORTHO® (Licence Ouverte Etalab 2.0)

Chemin de l'Adret LiDAR hillshade map with contours

Profile

The map, profile and gradient chart share one position — move your pointer over them and the marker follows. Colors are the gradient bands; the shaded span is the steepest 25 m. Any 25 m figure is good to about a point either way (why).

Chemin de l'Adret elevation profile
Chemin de l'Adret rolling gradient profile
 

Measurement card

ElevationIGN LiDAR HD MNT 0.5 m — LiDAR HD — MNT (sol) et MNS (surface), 0,50 m (Institut national de l'information géographique et forestière), RGF93 / Lambert-93 EPSG:2154, altitudes IGN69
Resolution / CRS0.5 m grid, EPSG:2154; sampled every 1.0 m, bilinear interpolation
TilesE983-N6372, E983-N6373, E984-N6372, E984-N6373
Road centrelineOpenStreetMap (local PBF extract)
Quality statusevidence quality B; caveated windows: structure excluded, texture excluded
AnalysisOCL 0.1.0, analysis 0.1.0, run fr-alps4, calculated 2026-09-17

Provenance

{
  "analysis_version": "0.1.0",
  "sample_interval_m": 1.0,
  "interpolation": "bilinear",
  "smoothing": "none",
  "gradient_windows_m": [
    5.0,
    10.0,
    20.0,
    25.0,
    50.0,
    100.0
  ],
  "diagnostic_windows_m": [
    2.0,
    3.0
  ],
  "elevation_crs": "EPSG:2154",
  "elevation_resolution_m": 0.5,
  "elevation_tiles": [
    "data/cache/fr/ign-lidarhd_dtm_E983-N6372_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E983-N6373_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E984-N6372_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E984-N6373_0m5.tif"
  ],
  "calculated_at": "2026-09-17T02:37:22+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/block-batch-fr-alps4.osm.pbf",
  "osm_snapshot": "",
  "run_id": "fr-alps4",
  "elevation_provider": "IGN LiDAR HD MNT 0.5 m",
  "elevation_licence": "Licence Ouverte / Open Licence 2.0 (Etalab) \u2014 \u00a9 IGN, LiDAR HD (MNT/MNS), data.geopf.fr; reproduction autoris\u00e9e avec mention de la source et de la date",
  "elevation_dataset": "LiDAR HD \u2014 MNT (sol) et MNS (surface), 0,50 m (Institut national de l'information g\u00e9ographique et foresti\u00e8re), RGF93 / Lambert-93 EPSG:2154, altitudes IGN69",
  "elevation_vertical_datum": "IGN69",
  "elevation_tile_ids": [
    "E983-N6372",
    "E983-N6373",
    "E984-N6372",
    "E984-N6373"
  ],
  "elevation_blocks": [
    "21LHD8QO@2025-04-02"
  ],
  "ign_dalles": [
    "LHD_FXX_0983_6373_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0983_6374_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0984_6373_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0984_6374_MNT_O_0M50_LAMB93_IGN69"
  ],
  "ign_missions": [
    "21LHD8QO"
  ],
  "ign_editions": [
    "2025-04-02"
  ],
  "ign_dsm_edition": {
    "LHD_FXX_0983_6373_MNT_O_0M50_LAMB93_IGN69": "2025-04-02",
    "LHD_FXX_0983_6374_MNT_O_0M50_LAMB93_IGN69": "2025-04-02",
    "LHD_FXX_0984_6373_MNT_O_0M50_LAMB93_IGN69": "2025-04-02",
    "LHD_FXX_0984_6374_MNT_O_0M50_LAMB93_IGN69": "2025-04-02"
  },
  "climb_origin": "discovered",
  "structure_own_ways": "none \u2014 the route carried no way list; own decks unmasked",
  "carriageway": {
    "stations": 97,
    "stations_resolved": 97,
    "width_median_m": 4.75,
    "width_p10_m": 2.5,
    "width_min_m": 1.0,
    "width_max_m": 9.75,
    "bounded_share": 0.495,
    "unbounded_share": 0.505,
    "confidence_median": 0.0,
    "width_median_bounded_m": 5.0,
    "window_m": [
      289.0,
      314.0
    ],
    "width_at_max25_m": 4.25,
    "window_stations": 7,
    "single_track": false,
    "single_track_rule": "PROVISIONAL (2026-09-15): width_p10_m <= 3.0 m with bounded_share >= 0.6; recorded, not a rule",
    "status": "ok",
    "source": "dtm",
    "station_m": 25.0,
    "window_station_m": 5.0,
    "halfwidth_m": 6.0,
    "step_m": 0.25,
    "level_tol_m": 0.12,
    "break_min_m": 0.3,
    "stations_failed": 0,
    "hedge_to_hedge": {
      "stations": 97,
      "stations_resolved": 97,
      "width_median_m": 5.75,
      "width_p10_m": 1.25,
      "width_min_m": 0.5,
      "width_max_m": 12.0,
      "bounded_share": 0.897,
      "unbounded_share": 0.103,
      "confidence_median": 1.0,
      "width_median_bounded_m": 5.5,
      "window_m": [
        289.0,
        314.0
      ],
      "width_at_max25_m": 4.75,
      "window_stations": 7,
      "status": "ok",
      "source": "dsm",
      "station_m": 25.0,
      "window_station_m": 5.0,
      "halfwidth_m": 6.0,
      "step_m": 0.25,
      "level_tol_m": 0.5,
      "break_min_m": 0.3,
      "stations_failed": 0
    }
  },
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing"
}