Llanfihangel-y-Creuddyn to Pant-y-crug
1494.0 m · net rise 96.1 m · total ascent 122.9 m · overall 6.4% · confidence: good · Llanfihangel-y-Creuddyn · Dyfed · share
Shape: stepped — 46% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 307 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 28% 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) | ≈36% | 798–800 m | under overhead cover terrain reads 166.8% at 825–827 m across a structure — excluded |
| 3 m (diagnostic) | ≈32% | 798–801 m | under overhead cover terrain reads 138.9% at 825–828 m across a structure — excluded |
| 5 m | ≈26% | 133–138 m | under overhead cover terrain reads 103.3% at 823–828 m across a structure — excluded |
| 10 m | ≈26% | 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
This climb's data: OCL JSON — the full gradient ladder, quality flags and provenance in the OpenClimb Ladder format.
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
© 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": "2026-08-13T02:09:16+00:00",
"road_source": "extended-proposals-wales-routes/unnamed-lane-near-pen-y-garn.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_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"
],
"route_summit_trim_m": 1058.9,
"route_summit_trim_loss_m": 9.2,
"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.",
"license": "ODbL-1.0",
"license_url": "https://howsteep.org/licensing.html"
}