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

Col de la Ramaz from Mieussy

13216.4 m · net rise 911.3 m · total ascent 1041.6 m · overall 6.9% · evidence quality B (good) · Mieussy · Haute-Savoie · share

Shape: sustained — 40% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 159 m.

Not yet matched against documented climbs — the measurement stands on its own.

Gradient ladder what do windows mean?

Window	Maximum	Located at
2 m (diagnostic)	≈22%	8615–8617 m	under overhead cover terrain reads 622.7% at 8812–8814 m across a structure — excluded
3 m (diagnostic)	≈18%	8614–8617 m	under overhead cover terrain reads 497.3% at 8811–8814 m across a structure — excluded
5 m	≈15%	8612–8617 m	under overhead cover terrain reads 363.1% at 8811–8816 m across a structure — excluded
10 m	≈14%	8179–8189 m	under overhead cover terrain reads 199.2% at 8808–8818 m across a structure — excluded
20 m	≈13.5%	8174–8194 m	under overhead cover terrain reads 133.5% at 8834–8854 m across a structure — excluded
25 m	≈13.4%	8169–8194 m	under overhead cover terrain reads 131.4% at 8811–8836 m across a structure — excluded
50 m	≈13.0%	8160–8210 m	under overhead cover terrain reads 119.8% at 8810–8860 m across a structure — excluded
100 m	≈12.2%	8117–8217 m	under overhead cover terrain reads 83.5% at 8772–8872 m across a structure — excluded

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 throughout, according to BD TOPO®, IGN's national topographic database.

Access: Listed 2026-09-05 (inventory hunt wave 1): road audit — barrier lift_gate (no access tag) 0.0 m off route. Never silently ranked or dropped (Peter, 2026-08-27).

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 · Share this climb

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

Col de la Ramaz from Mieussy 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).

Measurement card

Elevation	IGN 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 / CRS	0.5 m grid, EPSG:2154; sampled every 1.0 m, bilinear interpolation
Tiles	E970-N6566, E970-N6567, E970-N6568, E971-N6565, E971-N6566, E971-N6567, E971-N6568, E972-N6565, E972-N6566, E972-N6567, E972-N6568, E973-N6568, E973-N6569, E974-N6568, E974-N6569, E975-N6568, E975-N6569, E976-N6568
Road centreline	OpenStreetMap (local PBF extract)
Quality status	evidence quality B; caveated windows: canopy or structure, structure excluded, texture excluded
Analysis	OCL 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_E970-N6566_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E970-N6567_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E970-N6568_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E971-N6565_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E971-N6566_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E971-N6567_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E971-N6568_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E972-N6565_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E972-N6566_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E972-N6567_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E972-N6568_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E973-N6568_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E973-N6569_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E974-N6568_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E974-N6569_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E975-N6568_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E975-N6569_0m5.tif",
    "data/cache/fr/ign-lidarhd_dtm_E976-N6568_0m5.tif"
  ],
  "calculated_at": "2026-09-17T01:54:50+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": [
    "E970-N6566",
    "E970-N6567",
    "E970-N6568",
    "E971-N6565",
    "E971-N6566",
    "E971-N6567",
    "E971-N6568",
    "E972-N6565",
    "E972-N6566",
    "E972-N6567",
    "E972-N6568",
    "E973-N6568",
    "E973-N6569",
    "E974-N6568",
    "E974-N6569",
    "E975-N6568",
    "E975-N6569",
    "E976-N6568"
  ],
  "elevation_blocks": [
    "21LHD5QK2@2025-06-13"
  ],
  "ign_dalles": [
    "LHD_FXX_0970_6567_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0970_6568_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0970_6569_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0971_6566_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0971_6567_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0971_6568_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0971_6569_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0972_6566_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0972_6567_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0972_6568_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0972_6569_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0973_6569_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0973_6570_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0974_6569_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0974_6570_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0975_6569_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0975_6570_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0976_6569_MNT_O_0M50_LAMB93_IGN69"
  ],
  "ign_missions": [
    "21LHD5QK2"
  ],
  "ign_editions": [
    "2025-06-13"
  ],
  "ign_dsm_edition": {
    "LHD_FXX_0970_6567_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0970_6568_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0970_6569_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0971_6566_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0971_6567_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0971_6568_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0971_6569_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0972_6566_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0972_6567_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0972_6568_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0972_6569_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0973_6569_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0973_6570_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0974_6569_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0974_6570_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0975_6569_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0975_6570_MNT_O_0M50_LAMB93_IGN69": "2025-06-13",
    "LHD_FXX_0976_6569_MNT_O_0M50_LAMB93_IGN69": "2025-06-13"
  },
  "climb_origin": "named-pass",
  "structure_own_ways": "none \u2014 the route carried no way list; own decks unmasked",
  "carriageway": {
    "stations": 535,
    "stations_resolved": 535,
    "width_median_m": 7.5,
    "width_p10_m": 5.85,
    "width_min_m": 0.5,
    "width_max_m": 12.0,
    "bounded_share": 0.402,
    "unbounded_share": 0.598,
    "confidence_median": 0.0,
    "width_median_bounded_m": 7.25,
    "window_m": [
      8169.0,
      8194.0
    ],
    "width_at_max25_m": 9.75,
    "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": 535,
      "stations_resolved": 535,
      "width_median_m": 9.25,
      "width_p10_m": 4.75,
      "width_min_m": 0.5,
      "width_max_m": 12.0,
      "bounded_share": 0.581,
      "unbounded_share": 0.419,
      "confidence_median": 1.0,
      "width_median_bounded_m": 8.0,
      "window_m": [
        8169.0,
        8194.0
      ],
      "width_at_max25_m": 8.75,
      "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"
}