BETA — measurements and names under active refinement. Seen a sign, a gate, or a better name? Report it (photos welcome).
Roman Way
565.6 m · gain 21.6 m · overall 3.8% · Caerllion · Casnewydd - Newport
Shape: sustained — 44% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 34 m.
Documented on the ground — tag: 30% (2026). Signs get repainted and tags get retagged, so the date is part of the fact; on no cycling list we know of.
Gradient ladder what do windows mean?
| Window | Maximum | Located at | |
|---|---|---|---|
| 2 m (diagnostic) | 15.1% | 509–511 m | |
| 3 m (diagnostic) | 14.5% | 504–507 m | |
| 5 m | 13.9% | 505–510 m | |
| 10 m | 13.4% | 502–512 m | |
| 20 m | 12.5% | 496–516 m | |
| 25 m | 12.1% | 491–516 m | |
| 50 m | 10.3% | 476–526 m | |
| 100 m | 9.0% | 428–528 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
Reported values vs. measurement
| Source | Claim | Evidence | Best-matching window |
|---|---|---|---|
| OSM incline tag (bulk changeset) | 30% | mapper_estimate | 2 m (+14.9 pp) |
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_5_333191_20201201dtm.tif"
],
"calculated_at": "2026-08-12T09:11:52+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_5_333191_20201201dtm.tif"
],
"elevation_capture_dates": [
"01-12-2020"
],
"climb_origin": "osm_incline",
"signed_gradient_pct": 30,
"signed_source": "OSM incline tag ONLY \u2014 same bulk changeset 112097443 as Trinity View; same user had previously tagged this way 15% (changeset 91470353, 2020) then raised it to 30%. Mapper estimate, NOT road_sign.",
"notes": "Measured max 5 m 13.9%. The 15%\u219230% self-revision by the same mapper shows these are impressions, not sign readings. 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."
}