Llanfihangel-y-Creuddyn to Pant-y-crug
2552.9 m · gain 86.9 m · overall 3.4% · Cwm Seiri · Sir Ceredigion - Ceredigion
Shape: sustained — 41% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 307 m.
An unlisted find of this survey, on no list we know of. It was discovered by analysing LiDAR terrain data and cross-checked against the OS road network, surface models and map tags — but despite all that, 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 that someone is you, 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 22% 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, not wrong. Longer windows average over more clean ground and are steadier.
Gradient ladder what do windows mean?
| Window | Maximum | Located at | |
|---|---|---|---|
| 2 m (diagnostic) | ≈35.6% | 798–800 m | under overhead cover terrain reads 166.8% at 825–827 m across a structure — excluded |
| 3 m (diagnostic) | ≈31.8% | 798–801 m | under overhead cover terrain reads 138.9% at 825–828 m across a structure — excluded |
| 5 m | ≈26.4% | 133–138 m | under overhead cover terrain reads 103.3% at 823–828 m across a structure — excluded |
| 10 m | ≈26.0% | 132–142 m | under overhead cover terrain reads 51.9% at 822–832 m across a structure — excluded |
| 20 m | ≈25.5% | 131–151 m | under overhead cover terrain reads 26.3% at 822–842 m across a structure — excluded |
| 25 m | 25.4% | 121–146 m | |
| 50 m | 24.6% | 116–166 m | |
| 100 m | ≈23.0% | 100–200 m | under overhead cover |
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
© 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_22_266276_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_266277_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_266278_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_23_265276_20220117dtm.tif",
"data/cache/wales/dtm_1m/wg_del_23_265277_20220117dtm.tif",
"data/cache/wales/dtm_1m/wg_del_23_265278_20220117dtm.tif"
],
"calculated_at": "2026-08-12T09:12:12+00:00",
"road_source": "OpenStreetMap (local PBF extract)",
"road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
"osm_pbf_path": "data/cache/pbf/wales-2026-08-11.osm.pbf",
"osm_snapshot": "2026-08-10T20:21:40Z",
"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_22_266276_20220114dtm.tif",
"wg_del_22_266277_20220114dtm.tif",
"wg_del_22_266278_20220114dtm.tif",
"wg_del_23_265276_20220117dtm.tif",
"wg_del_23_265277_20220117dtm.tif",
"wg_del_23_265278_20220117dtm.tif"
],
"elevation_capture_dates": [
"14-01-2022",
"17-01-2022"
],
"climb_origin": "discovered",
"notes": "Second in Rheidol sweep by max 100 m (22.5%); no incline tag. EXTENDED by graph walk: +2 segment(s) at base, +1 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). RENAMED 2026-08-11 (Peter approved): auto-name \"Unnamed lane near Pen-y-garn\" was a phantom \u2014 no Pen-y-garn within 13 km in OSM (nodes AND ways), OS Open Names, or the RCAHMW historic place-name index; nearest is the 610 m summit near Devil's Bridge (SOTA GW/MW-004), 13.8 km east. Endpoints verify: Llanfihangel-y- Creuddyn and Pant-y-crug both within metres of the route ends."
}