{
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 "name": "Lane near Blaenllechau",
 "slug": "discovered-lane-51-6658-3-4510",
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 },
 "diagnostic_note": "Windows <=3 m are at raster-noise scale (1-sigma raster noise alone is roughly +/-7 pp at 2 m and +/-5 pp at 3 m on a 1 m DTM). Diagnostic use only: never a headline or ranking value.",
 "quality_summary": {
  "overhead_obstruction": {
   "obstruction_threshold_m": 2.0,
   "obstructed_fraction": 0.296,
   "obstruction_max_height_m": 9.87,
   "flagged_windows_m": [
    2,
    3,
    5,
    10,
    20,
    25,
    50,
    100
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  },
  "review": [
   "human_review: Line-offset campaign 2026-08-20 (Wales leg): ranked window still measures well off any OS Open Roads link after re-siting \u2014 OSM and OR disagree where (or whether) the road runs there. Quarantined pending adjudication."
  ],
  "extent": [
   "may_start_earlier"
  ]
 },
 "provenance": {
  "analysis_version": "0.1.0",
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  "interpolation": "bilinear",
  "smoothing": "none",
  "gradient_windows_m": [
   5.0,
   10.0,
   20.0,
   25.0,
   50.0,
   100.0
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  "diagnostic_windows_m": [
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  "elevation_crs": "EPSG:27700",
  "elevation_resolution_m": 1.0,
  "elevation_tiles": [
   "data/cache/wales/dtm_1m/wg_del_5_299197_20201224dtm.tif"
  ],
  "calculated_at": "2026-08-20T23:10:46+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_299197_20201224dtm.tif"
  ],
  "elevation_capture_dates": [
   "24-12-2020"
  ],
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 21.2% over 200 m (Terrain 50), gain 20.1 m over 95 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): qualified-steep. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (51.6658, -3.4510)'.",
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing.html"
 }
}