BETA — measurements and names under active refinement. Seen a sign, a gate, or a better name? Report it (photos welcome).

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Lane near Llanglydwen°

1839.2 m · gain 96.0 m · overall 5.2% · Llanglydwen · Sir Gaerfyrddin - Carmarthenshire

Shape: sustained — 41% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 156 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 (51.9092, -4.6293)'). Corrections welcome.

Gradient ladder what do windows mean?

WindowMaximumLocated at
2 m (diagnostic)33.4%139–141 m
3 m (diagnostic)29.9%139–142 m
5 m25.9%62–67 m
10 m23.0%59–69 m
20 m20.4%48–68 m
25 m20.3%42–67 m
50 m18.4%115–165 m
100 m16.8%106–206 m

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

Lane near Llanglydwen LiDAR hillshade map with contours

Profile

Lane near Llanglydwen elevation profile Lane near Llanglydwen rolling gradient 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_6_218226_20210210dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_6_219226_20210210dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_6_220226_20210210dtm.tif"
  ],
  "calculated_at": "2026-08-12T09:07:28+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_6_218226_20210210dtm.tif",
    "wg_del_6_219226_20210210dtm.tif",
    "wg_del_6_220226_20210210dtm.tif"
  ],
  "elevation_capture_dates": [
    "10-02-2021",
    "11-02-2021"
  ],
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 15.5% over 200 m (Terrain 50), gain 35.4 m over 600 m way. EXTENDED by graph walk: +0 segment(s) at base, +1 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. ADOPTED (notable slice 2026-08-11): clean-steep. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (51.9092, -4.6293)'.",
  "naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (51.9092, -4.6293)'"
}