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Paved · ranked
10445.5 m · net rise 671.3 m · total ascent 696.1 m · overall 6.4% · evidence quality B (good) · Châtel · Haute-Savoie
Shape: sustained — 35% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 118 m.
Not yet matched against documented climbs — the measurement stands on its own.
Col de Bassachaux from Châtel (Châtel, Haute-Savoie) is 10445.5 m long at 6.4% overall; its steepest 25 m averages ≈13.4% and its steepest 100 m ≈11.8%, measured from IGN's LiDAR HD 0.5 m laser surveys along the mapped road centreline.
Gradient ladder what do windows mean?
| Window | Maximum | Located at | |
|---|---|---|---|
| 2 m (diagnostic) | ≈17% | 9891–9893 m | under overhead cover terrain reads 270.0% at 3108–3110 m across a structure — excluded |
| 3 m (diagnostic) | ≈15% | 9707–9710 m | under overhead cover terrain reads 181.5% at 3107–3110 m across a structure — excluded |
| 5 m | ≈15% | 9705–9710 m | under overhead cover terrain reads 108.8% at 3107–3112 m across a structure — excluded |
| 10 m | ≈14% | 9701–9711 m | under overhead cover terrain reads 54.7% at 3107–3117 m across a structure — excluded |
| 20 m | ≈13.8% | 9698–9718 m | under overhead cover terrain reads 27.5% at 3107–3127 m across a structure — excluded |
| 25 m | ≈13.4% | 9692–9717 m | under overhead cover terrain reads 22.2% at 3785–3810 m across a structure — excluded |
| 50 m | ≈12.4% | 9669–9719 m | under overhead cover terrain reads 14.2% at 4627–4677 m across a structure — excluded |
| 100 m | ≈11.8% | 9618–9718 m | under overhead cover |
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 · Share this climb
Route colour = gradient over a 25 m window: <10% 10–20% 20–25% ≥25%
Route line = the road surface as the LiDAR survey finds it. Basemap roads are for orientation and may sit a few metres off.
© OpenStreetMap contributors · topo tiles © OpenTopoMap (CC-BY-SA) · vector tiles OpenFreeMap · aerial imagery © IGN, BD ORTHO® (Licence Ouverte Etalab 2.0)
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 | E990-N6575, E990-N6576, E991-N6575, E991-N6576, E991-N6577, E991-N6578, E992-N6575, E992-N6576, E992-N6577, E992-N6578, E992-N6579, E993-N6578, E993-N6579, E993-N6580, E994-N6579, E994-N6580 |
| Road centreline | OpenStreetMap (local PBF extract) |
| Quality status | evidence quality B; caveated windows: structure excluded, structure excluded min |
| Analysis | OCL 0.1.0, analysis 0.1.0, run remeasure-260929c-fr, calculated 2026-09-29 |
Provenance
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"structure_mask_ranges_m": [
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