Erwyd to Llangynog
5937.0 m · net rise 308.1 m · total ascent 345.0 m · overall 5.2% · confidence: good
Shape: sustained — 42% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 183 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 the OS road network, surface models and map tags, 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 6% 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?
| Window | Maximum | Located at | |
|---|---|---|---|
| 2 m (diagnostic) | 27% | 530–532 m | |
| 3 m (diagnostic) | 23% | 2656–2659 m | |
| 5 m | ≈20% | 406–411 m | under overhead cover |
| 10 m | ≈20% | 403–413 m | under overhead cover |
| 20 m | ≈19.2% | 401–421 m | under overhead cover |
| 25 m | ≈18.9% | 403–428 m | under overhead cover |
| 50 m | ≈18.2% | 378–428 m | under overhead cover |
| 100 m | ≈17.4% | 360–460 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.
Ridden it, or know better? Submit data for this climb no account needed
© OpenStreetMap contributors · topo tiles © OpenTopoMap (CC-BY-SA) · vector tiles OpenFreeMap
Profile
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:27700",
"elevation_resolution_m": 1.0,
"elevation_tiles": [
"data/cache/wales/dtm_1m/wg_del_16_301243_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_301244_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_301245_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_301246_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_302243_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_302244_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_302245_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_302246_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_303243_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_303244_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_303245_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_303246_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_304243_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_304244_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_304245_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_304246_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_305243_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_305244_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_305245_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_305246_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_306243_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_306244_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_306245_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_306246_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_308245_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_16_308246_20210329dtm.tif",
"data/cache/wales/dtm_1m/wg_del_18_307243_20211201dtm.tif",
"data/cache/wales/dtm_1m/wg_del_18_307244_20211201dtm.tif",
"data/cache/wales/dtm_1m/wg_del_18_307245_20211201dtm.tif",
"data/cache/wales/dtm_1m/wg_del_18_307246_20211201dtm.tif",
"data/cache/wales/dtm_1m/wg_del_18_308243_20211201dtm.tif",
"data/cache/wales/dtm_1m/wg_del_18_308244_20211201dtm.tif"
],
"calculated_at": "2026-08-13T02:10:18+00:00",
"road_source": "wales-discovered-adopted-routes/discovered-lane-52-0976-3-3886.geojson",
"elevation_provider": "Welsh Government",
"elevation_dataset": "Welsh Government LiDAR 1m DTM (2020-2023)",
"elevation_licence": "Open Government Licence v3 \u2014 \u00a9 Crown copyright Welsh Government",
"elevation_catalogue_layer": "geonode:welsh_government_lidar_tile_catalogue_2020_2023",
"elevation_tile_ids": [
"wg_del_16_301243_20210329dtm.tif",
"wg_del_16_301244_20210329dtm.tif",
"wg_del_16_301245_20210329dtm.tif",
"wg_del_16_301246_20210329dtm.tif",
"wg_del_16_302243_20210329dtm.tif",
"wg_del_16_302244_20210329dtm.tif",
"wg_del_16_302245_20210329dtm.tif",
"wg_del_16_302246_20210329dtm.tif",
"wg_del_16_303243_20210329dtm.tif",
"wg_del_16_303244_20210329dtm.tif",
"wg_del_16_303245_20210329dtm.tif",
"wg_del_16_303246_20210329dtm.tif",
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"wg_del_16_305243_20210329dtm.tif",
"wg_del_16_305244_20210329dtm.tif",
"wg_del_16_305245_20210329dtm.tif",
"wg_del_16_305246_20210329dtm.tif",
"wg_del_16_306243_20210329dtm.tif",
"wg_del_16_306244_20210329dtm.tif",
"wg_del_16_306245_20210329dtm.tif",
"wg_del_16_306246_20210329dtm.tif",
"wg_del_16_308245_20210329dtm.tif",
"wg_del_16_308246_20210329dtm.tif",
"wg_del_18_307243_20211201dtm.tif",
"wg_del_18_307244_20211201dtm.tif",
"wg_del_18_307245_20211201dtm.tif",
"wg_del_18_307246_20211201dtm.tif",
"wg_del_18_308243_20211201dtm.tif",
"wg_del_18_308244_20211201dtm.tif"
],
"elevation_capture_dates": [
"02-12-2021",
"29-03-2021",
"30-03-2021"
],
"route_summit_trim_m": 3842.5,
"route_summit_trim_loss_m": 36.7,
"climb_origin": "discovered",
"notes": "Coarse pass: max 14.7% over 200 m (Terrain 50), gain 71.3 m over 6505 m way. EXTENDED by graph walk: +1 segment(s) at base, +4 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 4 overlapping proposal(s): discovered-lane-52-0829-3-3655, discovered-lane-52-0835-3-3361, discovered-lane-52-0862-3-3713, discovered-lane-52-0967-3-4301 ADOPTED (notable slice 2026-08-11): big-gain. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (52.0976, -3.3886)'."
}