Garth to Cwmsymlog°
4879.8 m · gain 272.6 m · overall 5.6% · Pen-rhiw-newydd · Sir Ceredigion - Ceredigion
Shape: sustained — 32% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 113 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 (52.4380, -3.9671)'). Corrections welcome.
needs review short_window_divergence — treat short-window maxima here as provisional.
Gradient ladder what do windows mean?
| Window | Maximum | Located at | |
|---|---|---|---|
| 2 m (diagnostic) | 50.1% | 4006–4008 m | |
| 3 m (diagnostic) | 41.2% | 4005–4008 m | |
| 5 m | 31.5% | 4004–4009 m | |
| 10 m | 22.9% | 4003–4013 m | |
| 20 m | 19.2% | 4004–4024 m | |
| 25 m | 18.5% | 4004–4029 m | |
| 50 m | 16.6% | 4006–4056 m | |
| 100 m | 14.0% | 3970–4070 m |
may_start_earliermay_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_266283_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_266284_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_267283_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_267284_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_268283_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_268284_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_269283_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_269284_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_270283_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_22_270284_20220114dtm.tif",
"data/cache/wales/dtm_1m/wg_del_23_265283_20220117dtm.tif",
"data/cache/wales/dtm_1m/wg_del_23_265284_20220117dtm.tif"
],
"calculated_at": "2026-08-12T09:08:25+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_266283_20220114dtm.tif",
"wg_del_22_266284_20220114dtm.tif",
"wg_del_22_267283_20220114dtm.tif",
"wg_del_22_267284_20220114dtm.tif",
"wg_del_22_268283_20220114dtm.tif",
"wg_del_22_268284_20220114dtm.tif",
"wg_del_22_269283_20220114dtm.tif",
"wg_del_22_269284_20220114dtm.tif",
"wg_del_22_270283_20220114dtm.tif",
"wg_del_22_270284_20220114dtm.tif",
"wg_del_23_265283_20220117dtm.tif",
"wg_del_23_265284_20220117dtm.tif"
],
"elevation_capture_dates": [
"14-01-2022",
"17-01-2022"
],
"climb_origin": "discovered",
"notes": "Coarse pass: max 11.5% over 200 m (Terrain 50), gain 190.1 m over 3557 m way. EXTENDED by graph walk: +4 segment(s) at base, +2 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 4 overlapping proposal(s): discovered-lane-52-4368-3-9769, discovered-lane-52-4375-3-9414, discovered-lane-52-4384-3-9870, discovered-lane-52-4392-3-9084 ADOPTED (notable slice 2026-08-11): big-gain. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (52.4380, -3.9671)'.",
"naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (52.4380, -3.9671)'"
}