Lane near Cwrt
1015.4 m · gain 93.9 m · overall 9.2% · Cwm Ffernol · Gwynedd
Shape: sustained — 34% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 144 m.
Documented on the ground — tag: 20% (2026). Signs get repainted and tags get retagged, so the date is part of the fact; on no cycling list we know of.
≈ Overhead cover (tree canopy or structures) spans 26% 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) | 39.7% | 956–958 m | |
| 3 m (diagnostic) | 39.9% | 956–959 m | |
| 5 m | 37.1% | 955–960 m | |
| 10 m | 31.0% | 951–961 m | |
| 20 m | 25.6% | 950–970 m | |
| 25 m | 24.4% | 948–973 m | |
| 50 m | 20.0% | 935–985 m | |
| 100 m | 17.5% | 874–974 m |
may_continue_beyond_end 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_266299_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_267299_20220114dtm.tif"
],
"calculated_at": "2026-08-12T09:12:08+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_266299_20220114dtm.tif",
"wg_del_22_267299_20220114dtm.tif"
],
"elevation_capture_dates": [
"14-01-2022"
],
"climb_origin": "osm_incline",
"signed_gradient_pct": 20.0,
"signed_source": "OSM incline tag 20% (editors=1, first tagged 2018-06-10)",
"notes": "Promoted automatically from triage verdict=validated. Named from nearest OSM place node (Cwrt); originally unnamed at (52.5795, -3.966). EXTENDED by graph walk: +2 segment(s) at base, +0 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting."
}