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Col des Issartets from Aumont-Aubrac

5441.0 m · net rise 117.7 m · total ascent 165.3 m · overall 2.2% · evidence quality B (good) · Peyre en Aubrac · Lozère ·

Shape: sustained — 41% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 26 m.

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

Gradient ladder what do windows mean?

WindowMaximumLocated at
2 m (diagnostic)≈8%3784–3786 munder overhead cover terrain reads 272.4% at 1490–1492 m across a structure — excluded
3 m (diagnostic)≈7%3985–3988 munder overhead cover terrain reads 183.6% at 1490–1493 m across a structure — excluded
5 m≈7%4275–4280 munder overhead cover terrain reads 111.5% at 1490–1495 m across a structure — excluded
10 m≈6%3768–3778 munder overhead cover terrain reads 57.9% at 1490–1500 m across a structure — excluded
20 m≈5.9%4525–4545 munder overhead cover terrain reads 31.0% at 1490–1510 m across a structure — excluded
25 m≈5.8%4522–4547 munder overhead cover terrain reads 25.6% at 1490–1515 m across a structure — excluded
50 m≈5.6%3985–4035 munder overhead cover terrain reads 14.8% at 1490–1540 m across a structure — excluded
100 m≈5.4%3953–4053 munder overhead cover terrain reads 9.3% at 1490–1590 m across a structure — excluded

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.

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)

Col des Issartets from Aumont-Aubrac 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).

Col des Issartets from Aumont-Aubrac elevation profile
Col des Issartets from Aumont-Aubrac 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
TilesE719-N6394, E719-N6395, E719-N6396, E720-N6394, E720-N6395, E720-N6396, E720-N6397, E721-N6397, E721-N6398, E722-N6398
Road centrelineOpenStreetMap (local PBF extract)
Quality statusevidence quality B; caveated windows: structure excluded, structure excluded min
AnalysisOCL 0.1.0, analysis 0.1.0, run fr-mc5, calculated 2026-09-22

Provenance

{
  "analysis_version": "0.1.0",
  "run_manifest": {
    "manifest_version": "1",
    "code_git_sha": "1cc9fdcd6556a02163cb21acb2293cad3067d2a1",
    "code_git_dirty": "false",
    "analysis_version": "0.1.0",
    "analysis_config_digest": "sha256:8c94015b54267da4",
    "python": "3.14.4",
    "numpy": "2.5.3",
    "rasterio": "1.5.1",
    "pyproj": "3.8.0",
    "laspy": "2.7.0",
    "shapely": "2.1.2",
    "pyosmium": "4.3.1",
    "libosmium": "2.23.1",
    "gdal": "3.12.4",
    "proj": "9.8.1",
    "run_id": "fr-mc5",
    "road_pbf": "block-batch-fr-mc5.osm.pbf",
    "region_key": "france",
    "crs": "EPSG:2154",
    "elevation_provider_key": "ign-lidarhd",
    "tile_index": "wms-grid",
    "authority": "bdtopo",
    "registry_pbf": "france-vosges-2026-09-16.osm.pbf",
    "tile_index_snapshot": "sha256:af4eae1f5df9e232"
  },
  "sample_interval_m": 1.0,
  "interpolation": "bilinear",
  "smoothing": "none",
  "gradient_windows_m": [
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    10.0,
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    25.0,
    50.0,
    100.0
  ],
  "diagnostic_windows_m": [
    2.0,
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  ],
  "elevation_crs": "EPSG:2154",
  "elevation_resolution_m": 0.5,
  "elevation_tiles": [
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    "data/cache/fr/ign-lidarhd_dtm_E719-N6395_0m5@21LHD4LN-2025-02-10.tif",
    "data/cache/fr/ign-lidarhd_dtm_E719-N6396_0m5@21LHD4LN-2025-02-10.tif",
    "data/cache/fr/ign-lidarhd_dtm_E720-N6394_0m5@21LHD4LN-2025-02-10.tif",
    "data/cache/fr/ign-lidarhd_dtm_E720-N6395_0m5@21LHD4LN-2025-02-10.tif",
    "data/cache/fr/ign-lidarhd_dtm_E720-N6396_0m5@21LHD4LN-2025-02-10.tif",
    "data/cache/fr/ign-lidarhd_dtm_E720-N6397_0m5@21LHD4LN-2025-02-10.tif",
    "data/cache/fr/ign-lidarhd_dtm_E721-N6397_0m5@21LHD4LN-2025-02-10.tif",
    "data/cache/fr/ign-lidarhd_dtm_E721-N6398_0m5@21LHD4LN-2025-02-10.tif",
    "data/cache/fr/ign-lidarhd_dtm_E722-N6398_0m5@21LHD4LN-2025-02-10.tif"
  ],
  "calculated_at": "2026-09-22T16:08:24+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/block-batch-fr-mc5.osm.pbf",
  "osm_snapshot": "",
  "run_id": "fr-mc5",
  "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": [
    "E719-N6394",
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    "E719-N6396",
    "E720-N6394",
    "E720-N6395",
    "E720-N6396",
    "E720-N6397",
    "E721-N6397",
    "E721-N6398",
    "E722-N6398"
  ],
  "elevation_blocks": [
    "21LHD4LN@2025-02-10"
  ],
  "ign_dalles": [
    "LHD_FXX_0719_6395_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0719_6396_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0719_6397_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0720_6395_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0720_6396_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0720_6397_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0720_6398_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0721_6398_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0721_6399_MNT_O_0M50_LAMB93_IGN69",
    "LHD_FXX_0722_6399_MNT_O_0M50_LAMB93_IGN69"
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  "ign_missions": [
    "21LHD4LN"
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  "ign_editions": [
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  "ign_dsm_edition": {
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    "LHD_FXX_0719_6396_MNT_O_0M50_LAMB93_IGN69": "2025-02-10",
    "LHD_FXX_0719_6397_MNT_O_0M50_LAMB93_IGN69": "2025-02-10",
    "LHD_FXX_0720_6395_MNT_O_0M50_LAMB93_IGN69": "2025-02-10",
    "LHD_FXX_0720_6396_MNT_O_0M50_LAMB93_IGN69": "2025-02-10",
    "LHD_FXX_0720_6397_MNT_O_0M50_LAMB93_IGN69": "2025-02-10",
    "LHD_FXX_0720_6398_MNT_O_0M50_LAMB93_IGN69": "2025-02-10",
    "LHD_FXX_0721_6398_MNT_O_0M50_LAMB93_IGN69": "2025-02-10",
    "LHD_FXX_0721_6399_MNT_O_0M50_LAMB93_IGN69": "2025-02-10",
    "LHD_FXX_0722_6399_MNT_O_0M50_LAMB93_IGN69": "2025-02-10"
  },
  "route_summit_trim_m": 59.7,
  "route_summit_trim_loss_m": 6.3,
  "climb_origin": "named-pass",
  "structure_own_ways": 7,
  "structure_mask_ranges_m": [
    [
      2261.8,
      2307.3
    ]
  ],
  "mask_basin_extension_m": 24.0,
  "carriageway": {
    "stations": 224,
    "stations_resolved": 224,
    "width_median_m": 9.75,
    "width_p10_m": 8.0,
    "width_min_m": 4.0,
    "width_max_m": 12.0,
    "bounded_share": 0.013,
    "unbounded_share": 0.987,
    "confidence_median": 0.0,
    "width_median_bounded_m": 8.75,
    "window_m": [
      4522.0,
      4547.0
    ],
    "width_at_max25_m": 10.25,
    "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": 224,
      "stations_resolved": 224,
      "width_median_m": 12.0,
      "width_p10_m": 10.25,
      "width_min_m": 7.5,
      "width_max_m": 12.0,
      "bounded_share": 0.022,
      "unbounded_share": 0.978,
      "confidence_median": 0.0,
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      "window_m": [
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        4547.0
      ],
      "width_at_max25_m": 12.0,
      "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"
}