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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": {
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  "review": [
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  "interpolation": "bilinear",
  "smoothing": "none",
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  "elevation_crs": "EPSG:27700",
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  "elevation_tiles": [
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  "calculated_at": "2026-08-12T00:52:16+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": [
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  "elevation_capture_dates": [
   "11-01-2022"
  ],
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 17.4% over 200 m (Terrain 50), gain 86.4 m over 974 m way. 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.",
  "naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (52.8540, -3.6585)'"
 },
 "area": {
  "place": "Llanuwchllyn",
  "county": "Gwynedd - Gwynedd"
 },
 "reported_claims": [],
 "confidence": "U",
 "shape": {
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  "concentration_window_frac": 0.25,
  "longest_pitch_10pct_m": 238.0,
  "shape_class": "sustained"
 }
}