Llanybydder to Mynydd Llanybyther°
6003.5 m · gain 285.6 m · overall 4.8% · Ceunant Fâch · Sir Gaerfyrddin - Carmarthenshire
Shape: sustained — 34% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 101 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.
° The name is provisional: this climb appears on no list we know of, so it was named from nearby map places. There is no evidence of local usage — (auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (52.0519, -4.1334)'). Corrections welcome.
≈ Overhead cover (tree canopy or structures) spans 9% 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) | 36.1% | 5022–5024 m | |
| 3 m (diagnostic) | 31.0% | 5021–5024 m | |
| 5 m | 26.3% | 5301–5306 m | |
| 10 m | 22.7% | 5300–5310 m | |
| 20 m | 17.3% | 5296–5316 m | |
| 25 m | 15.2% | 5290–5315 m | |
| 50 m | 13.3% | 2603–2653 m | |
| 100 m | ≈12.1% | 2574–2674 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
© 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_28_252239_20220315dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_252240_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_252241_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_252242_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_252243_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_253239_20220315dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_253240_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_253241_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_253242_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_253243_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_254239_20220315dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_254240_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_254241_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_254242_20220314dtm.tif",
"data/cache/wales/dtm_1m/wg_del_28_254243_20220314dtm.tif"
],
"calculated_at": "2026-08-12T09:07:45+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_28_252239_20220315dtm.tif",
"wg_del_28_252240_20220314dtm.tif",
"wg_del_28_252241_20220314dtm.tif",
"wg_del_28_252242_20220314dtm.tif",
"wg_del_28_252243_20220314dtm.tif",
"wg_del_28_253239_20220315dtm.tif",
"wg_del_28_253240_20220314dtm.tif",
"wg_del_28_253241_20220314dtm.tif",
"wg_del_28_253242_20220314dtm.tif",
"wg_del_28_253243_20220314dtm.tif",
"wg_del_28_254239_20220315dtm.tif",
"wg_del_28_254240_20220314dtm.tif",
"wg_del_28_254241_20220314dtm.tif",
"wg_del_28_254242_20220314dtm.tif",
"wg_del_28_254243_20220314dtm.tif"
],
"elevation_capture_dates": [
"15-03-2022"
],
"climb_origin": "discovered",
"notes": "Coarse pass: max 11.0% over 200 m (Terrain 50), gain 201.0 m over 4281 m way. EXTENDED by graph walk: +6 segment(s) at base, +1 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 3 overlapping proposal(s): discovered-lane-52-0647-4-1441, discovered-lane-52-0672-4-1361, heol-y-dderi ADOPTED (notable slice 2026-08-11): big-gain. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (52.0519, -4.1334)'.",
"naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (52.0519, -4.1334)'"
}