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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.",
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 "provenance": {
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  "interpolation": "bilinear",
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  "elevation_crs": "EPSG:27700",
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  "elevation_tiles": [
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   "data/cache/england/bulk_dtm_1m/SS7530.tif",
   "data/cache/england/bulk_dtm_1m/SS8030.tif"
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  "calculated_at": "2026-08-19T18:22:17+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/england-2026-08-12.osm.pbf",
  "osm_snapshot": "2026-08-12T20:21:46Z",
  "elevation_provider": "Environment Agency",
  "elevation_dataset": "EA LIDAR Composite DTM 1m (2022)",
  "elevation_licence": "Open Government Licence v3 \u2014 \u00a9 Environment Agency",
  "elevation_coverage_id": "13787b9a-26a4-4775-8523-806d13af58fc__Lidar_Composite_Elevation_DTM_1m",
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  "climb_origin": "discovered",
  "notes": "Coarse pass: max 11.2% over 200 m (Terrain 50), gain 29.2 m over 1897 m way. EXTENDED by graph walk: +1 segment(s) at base, +1 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. ADOPTED (England launch slice 2026-08-16): clean-steep. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (51.0530, -3.7133)'.",
  "naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (51.0530, -3.7133)'"
 },
 "area": {
  "place": "Twitchen",
  "county": "Devon"
 }
}