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  "calculated_at": "2026-08-12T09:11:49+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",
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  "elevation_capture_dates": [
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  "climb_origin": "named",
  "notes": "Abergwesyn pass, hairpinned section. Famous audax/sportive climb. EXTENDED by graph walk: +1 segment(s) at base, +0 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting."
 },
 "area": {
  "place": "Coed Nant-yr-hwch",
  "county": "Powys - Powys"
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 "reported_claims": [
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   "evidence_type": "road_sign",
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   "description": "25% gradient signage, Abergwesyn pass",
   "observation_date": "2011-10-19",
   "retrieved_at": "2026-08-10",
   "credibility": "Good: OSM incline=25% stable since 2011; well-known signed climb",
   "observed_via": "osm_tag_history"
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 ],
 "confidence": "A",
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  "concentration_window_frac": 0.25,
  "longest_pitch_10pct_m": 243.0,
  "shape_class": "sustained"
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}