{
 "ocl_version": "0.1.0",
 "name": "Dark Lane",
 "slug": "dark-lane",
 "confidence": "B",
 "reported_claims": [],
 "ladder": [
  {
   "window_m": 2.0,
   "max_gradient_pct": 41.36552880863178,
   "diagnostic": true,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 69.0,
   "end_distance_m": 71.0,
   "start_elevation_m": 166.42326664688323,
   "end_elevation_m": 167.25057722305587,
   "min_gradient_pct": -5.653115946144283
  },
  {
   "window_m": 3.0,
   "max_gradient_pct": 35.322759486164536,
   "diagnostic": true,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 68.0,
   "end_distance_m": 71.0,
   "start_elevation_m": 166.19089443847093,
   "end_elevation_m": 167.25057722305587,
   "min_gradient_pct": -4.480226806817693
  },
  {
   "window_m": 5.0,
   "max_gradient_pct": 28.34525368035088,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 66.0,
   "end_distance_m": 71.0,
   "start_elevation_m": 165.83331453903833,
   "end_elevation_m": 167.25057722305587,
   "min_gradient_pct": -3.816604582857508
  },
  {
   "window_m": 10.0,
   "max_gradient_pct": 23.53138382716878,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 76.0,
   "end_distance_m": 86.0,
   "start_elevation_m": 167.98625806565755,
   "end_elevation_m": 170.33939644837443,
   "min_gradient_pct": -2.906786698167707
  },
  {
   "window_m": 20.0,
   "max_gradient_pct": 22.530409546680517,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 66.0,
   "end_distance_m": 86.0,
   "start_elevation_m": 165.83331453903833,
   "end_elevation_m": 170.33939644837443,
   "min_gradient_pct": -2.279826582972646
  },
  {
   "window_m": 25.0,
   "max_gradient_pct": 21.72801989556524,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 67.0,
   "end_distance_m": 92.0,
   "start_elevation_m": 166.01118555592384,
   "end_elevation_m": 171.44319052981515,
   "min_gradient_pct": -1.9369495221558282
  },
  {
   "window_m": 50.0,
   "max_gradient_pct": 19.322170865914472,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 42.0,
   "end_distance_m": 92.0,
   "start_elevation_m": 161.78210509685792,
   "end_elevation_m": 171.44319052981515,
   "min_gradient_pct": -1.3791189517245357
  },
  {
   "window_m": 100.0,
   "max_gradient_pct": 15.237289145892476,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 35.0,
   "end_distance_m": 135.0,
   "start_elevation_m": 160.80719663918453,
   "end_elevation_m": 176.044485785077,
   "min_gradient_pct": -1.076815251735212
  }
 ],
 "shape": {
  "ascent_concentration": 0.759,
  "concentration_window_frac": 0.25,
  "longest_pitch_10pct_m": 71.0,
  "shape_class": "stinger"
 },
 "length_m": 660.461524850367,
 "start_elevation_m": 158.35071862246468,
 "end_elevation_m": 180.91908532947076,
 "endpoint_gain_m": 22.568366707006078,
 "overall_gradient_pct": 3.417060019070623,
 "accumulated_ascent_m": 26.220353164394226,
 "window_maxima": {
  "max_5m": {
   "gradient_pct": 28.34525368035088,
   "start_distance_m": 66.0,
   "end_distance_m": 71.0,
   "midpoint_distance_m": 68.5,
   "start_elevation_m": 165.83331453903833,
   "end_elevation_m": 167.25057722305587,
   "start_xy": [
    404515.32555739017,
    208538.07682269925
   ],
   "end_xy": [
    404515.19255141006,
    208533.07859269288
   ]
  },
  "max_10m": {
   "gradient_pct": 23.53138382716878,
   "start_distance_m": 76.0,
   "end_distance_m": 86.0,
   "midpoint_distance_m": 81.0,
   "start_elevation_m": 167.98625806565755,
   "end_elevation_m": 170.33939644837443,
   "start_xy": [
    404515.05868241005,
    208528.08038555653
   ],
   "end_xy": [
    404514.79267366097,
    208518.08392545683
   ]
  },
  "max_20m": {
   "gradient_pct": 22.530409546680517,
   "start_distance_m": 66.0,
   "end_distance_m": 86.0,
   "midpoint_distance_m": 76.0,
   "start_elevation_m": 165.83331453903833,
   "end_elevation_m": 170.33939644837443,
   "start_xy": [
    404515.32555739017,
    208538.07682269925
   ],
   "end_xy": [
    404514.79267366097,
    208518.08392545683
   ]
  },
  "max_25m": {
   "gradient_pct": 21.72801989556524,
   "start_distance_m": 67.0,
   "end_distance_m": 92.0,
   "midpoint_distance_m": 79.5,
   "start_elevation_m": 166.01118555592384,
   "end_elevation_m": 171.44319052981515,
   "start_xy": [
    404515.2986806488,
    208537.07718400634
   ],
   "end_xy": [
    404512.3751900576,
    208512.6176666782
   ]
  },
  "max_50m": {
   "gradient_pct": 19.322170865914472,
   "start_distance_m": 42.0,
   "end_distance_m": 92.0,
   "midpoint_distance_m": 67.0,
   "start_elevation_m": 161.78210509685792,
   "end_elevation_m": 171.44319052981515,
   "start_xy": [
    404514.5779330725,
    208561.98186703408
   ],
   "end_xy": [
    404512.3751900576,
    208512.6176666782
   ]
  },
  "max_100m": {
   "gradient_pct": 15.237289145892476,
   "start_distance_m": 35.0,
   "end_distance_m": 135.0,
   "midpoint_distance_m": 85.0,
   "start_elevation_m": 160.80719663918453,
   "end_elevation_m": 176.044485785077,
   "start_xy": [
    404513.4821000772,
    208568.89555912715
   ],
   "end_xy": [
    404493.50137889123,
    208473.9811677067
   ]
  }
 },
 "window_minima": {
  "min_5m": {
   "gradient_pct": -3.816604582857508,
   "start_distance_m": 617.0,
   "end_distance_m": 622.0,
   "midpoint_distance_m": 619.5,
   "start_elevation_m": 181.53927956701568,
   "end_elevation_m": 181.3484493378728,
   "start_xy": [
    404350.6268190024,
    208021.49115439088
   ],
   "end_xy": [
    404347.9047606135,
    208017.29706450406
   ]
  },
  "min_10m": {
   "gradient_pct": -2.906786698167707,
   "start_distance_m": 615.0,
   "end_distance_m": 625.0,
   "midpoint_distance_m": 620.0,
   "start_elevation_m": 181.59297321922526,
   "end_elevation_m": 181.3022945494085,
   "start_xy": [
    404351.71560035064,
    208023.1688177875
   ],
   "end_xy": [
    404346.27142095956,
    208014.78067864905
   ]
  },
  "min_20m": {
   "gradient_pct": -2.279826582972646,
   "start_distance_m": 614.0,
   "end_distance_m": 634.0,
   "midpoint_distance_m": 624.0,
   "start_elevation_m": 181.6109156359788,
   "end_elevation_m": 181.15495031938428,
   "start_xy": [
    404352.26028031704,
    208024.00746173898
   ],
   "end_xy": [
    404341.3713835766,
    208007.2315320537
   ]
  },
  "min_25m": {
   "gradient_pct": -1.9369495221558282,
   "start_distance_m": 612.0,
   "end_distance_m": 637.0,
   "midpoint_distance_m": 624.5,
   "start_elevation_m": 181.63857756813007,
   "end_elevation_m": 181.15434018759112,
   "start_xy": [
    404353.3488776402,
    208025.6852446608
   ],
   "end_xy": [
    404339.7385224534,
    208004.71483518087
   ]
  },
  "min_50m": {
   "gradient_pct": -1.3791189517245357,
   "start_distance_m": 599.0,
   "end_distance_m": 649.0,
   "midpoint_distance_m": 624.0,
   "start_elevation_m": 181.65794807189997,
   "end_elevation_m": 180.9683885960377,
   "start_xy": [
    404360.4264555062,
    208036.5897319295
   ],
   "end_xy": [
    404333.03722132934,
    207994.76728362168
   ]
  },
  "min_100m": {
   "gradient_pct": -1.076815251735212,
   "start_distance_m": 534.0,
   "end_distance_m": 634.0,
   "midpoint_distance_m": 584.0,
   "start_elevation_m": 182.2317655711195,
   "end_elevation_m": 181.15495031938428,
   "start_xy": [
    404395.81462298223,
    208091.11199022445
   ],
   "end_xy": [
    404341.3713835766,
    208007.2315320537
   ]
  }
 },
 "diagnostic_window_maxima": {
  "max_2m": {
   "gradient_pct": 41.36552880863178,
   "start_distance_m": 69.0,
   "end_distance_m": 71.0,
   "midpoint_distance_m": 70.0,
   "start_elevation_m": 166.42326664688323,
   "end_elevation_m": 167.25057722305587,
   "start_xy": [
    404515.24555913615,
    208535.0778898513
   ],
   "end_xy": [
    404515.19255141006,
    208533.07859269288
   ]
  },
  "max_3m": {
   "gradient_pct": 35.322759486164536,
   "start_distance_m": 68.0,
   "end_distance_m": 71.0,
   "midpoint_distance_m": 69.5,
   "start_elevation_m": 166.19089443847093,
   "end_elevation_m": 167.25057722305587,
   "start_xy": [
    404515.271686807,
    208536.07754840652
   ],
   "end_xy": [
    404515.19255141006,
    208533.07859269288
   ]
  }
 },
 "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": 0.086,
   "obstruction_max_height_m": 12.13,
   "flagged_windows_m": [
    2,
    3,
    5,
    20,
    25,
    50,
    100
   ]
  },
  "review": [],
  "extent": [
   "may_start_earlier"
  ]
 },
 "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/england/bulk_dtm_1m/SP0005.tif"
  ],
  "calculated_at": "2026-09-05T09:11:34+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/england-2026-08-27-roads.osm.pbf",
  "osm_snapshot": "2026-08-26T20:22:15Z",
  "run_id": "fix-260905-p4",
  "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",
  "elevation_tile_ids": [
   "SP0005.tif"
  ],
  "route_base_cut_m": 2651.0,
  "climb_origin": "discovered",
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing"
 },
 "area": {
  "place": "North Cerney",
  "county": "Gloucestershire"
 }
}