{
 "ocl_version": "0.1.0",
 "name": "Heol Ddu",
 "slug": "heol-ddu",
 "confidence": "B",
 "reported_claims": [],
 "ladder": [
  {
   "window_m": 2.0,
   "max_gradient_pct": 43.39988713969234,
   "diagnostic": true,
   "flags": [
    "structure_excluded_min",
    "canopy_or_structure"
   ],
   "start_distance_m": 636.0,
   "end_distance_m": 638.0,
   "start_elevation_m": 115.74816184374461,
   "end_elevation_m": 116.61615958653846,
   "min_gradient_pct": -28.779423171414464,
   "suppressed_min_gradient_pct": -48.82428301494457,
   "suppressed_min_location_m": [
    1368.0,
    1370.0
   ]
  },
  {
   "window_m": 3.0,
   "max_gradient_pct": 36.01083395081588,
   "diagnostic": true,
   "flags": [
    "structure_excluded_min",
    "canopy_or_structure"
   ],
   "start_distance_m": 635.0,
   "end_distance_m": 638.0,
   "start_elevation_m": 115.53583456801398,
   "end_elevation_m": 116.61615958653846,
   "min_gradient_pct": -18.056314914059612,
   "suppressed_min_gradient_pct": -37.154313672996864,
   "suppressed_min_location_m": [
    1368.0,
    1371.0
   ]
  },
  {
   "window_m": 5.0,
   "max_gradient_pct": 26.574566983115915,
   "diagnostic": false,
   "flags": [
    "structure_excluded_min",
    "suppression_unstable",
    "canopy_or_structure"
   ],
   "start_distance_m": 633.0,
   "end_distance_m": 638.0,
   "start_elevation_m": 115.28743123738266,
   "end_elevation_m": 116.61615958653846,
   "min_gradient_pct": -13.156358714084035,
   "suppressed_min_gradient_pct": -21.58988538682138,
   "suppressed_min_location_m": [
    1368.0,
    1373.0
   ]
  },
  {
   "window_m": 10.0,
   "max_gradient_pct": 21.242082702863456,
   "diagnostic": false,
   "flags": [
    "structure_excluded_min",
    "texture_excluded",
    "canopy_or_structure"
   ],
   "start_distance_m": 1768.0,
   "end_distance_m": 1778.0,
   "start_elevation_m": 174.44249713972448,
   "end_elevation_m": 176.56670541001083,
   "min_gradient_pct": -9.312879967594085,
   "suppressed_max_gradient_pct": 22.736061954087745,
   "suppressed_location_m": [
    593.0,
    603.0
   ],
   "suppressed_min_gradient_pct": -10.118778720882915,
   "suppressed_min_location_m": [
    1368.0,
    1378.0
   ]
  },
  {
   "window_m": 20.0,
   "max_gradient_pct": 18.45455280725048,
   "diagnostic": false,
   "flags": [
    "texture_excluded",
    "canopy_or_structure"
   ],
   "start_distance_m": 1759.0,
   "end_distance_m": 1779.0,
   "start_elevation_m": 173.08438451552962,
   "end_elevation_m": 176.77529507697972,
   "min_gradient_pct": -7.2706111179880395,
   "suppressed_max_gradient_pct": 20.840363829764925,
   "suppressed_location_m": [
    583.0,
    603.0
   ]
  },
  {
   "window_m": 25.0,
   "max_gradient_pct": 18.25248868879737,
   "diagnostic": false,
   "flags": [
    "texture_excluded",
    "canopy_or_structure"
   ],
   "start_distance_m": 1754.0,
   "end_distance_m": 1779.0,
   "start_elevation_m": 172.21217290478037,
   "end_elevation_m": 176.77529507697972,
   "min_gradient_pct": -5.999625802706987,
   "suppressed_max_gradient_pct": 20.416104837531407,
   "suppressed_location_m": [
    583.0,
    608.0
   ]
  },
  {
   "window_m": 50.0,
   "max_gradient_pct": 17.194733631537503,
   "diagnostic": false,
   "flags": [
    "structure_excluded_min",
    "texture_excluded",
    "canopy_or_structure"
   ],
   "start_distance_m": 238.0,
   "end_distance_m": 288.0,
   "start_elevation_m": 80.3474499291399,
   "end_elevation_m": 88.94481674490865,
   "min_gradient_pct": -3.0924876909628267,
   "suppressed_max_gradient_pct": 18.174411454381357,
   "suppressed_location_m": [
    569.0,
    619.0
   ],
   "suppressed_min_gradient_pct": -3.9508357926676467,
   "suppressed_min_location_m": [
    1.0,
    51.0
   ]
  },
  {
   "window_m": 100.0,
   "max_gradient_pct": 14.479824434170197,
   "diagnostic": false,
   "flags": [
    "structure_excluded_min",
    "texture_excluded",
    "canopy_or_structure"
   ],
   "start_distance_m": 188.0,
   "end_distance_m": 288.0,
   "start_elevation_m": 74.46499231073845,
   "end_elevation_m": 88.94481674490865,
   "min_gradient_pct": -2.3042180732196442,
   "suppressed_max_gradient_pct": 14.68308570035525,
   "suppressed_location_m": [
    547.0,
    647.0
   ],
   "suppressed_min_gradient_pct": -2.915897550563102,
   "suppressed_min_location_m": [
    1.0,
    101.0
   ]
  }
 ],
 "shape": {
  "ascent_concentration": 0.351,
  "concentration_window_frac": 0.25,
  "longest_pitch_10pct_m": 184.0,
  "shape_class": "sustained"
 },
 "length_m": 3241.9947759970773,
 "start_elevation_m": 73.55810711022008,
 "end_elevation_m": 265.4855547696797,
 "endpoint_gain_m": 191.92744765945963,
 "overall_gradient_pct": 5.920041854491646,
 "accumulated_ascent_m": 221.35580797144266,
 "window_maxima": {
  "max_5m": {
   "gradient_pct": 26.574566983115915,
   "start_distance_m": 633.0,
   "end_distance_m": 638.0,
   "midpoint_distance_m": 635.5,
   "start_elevation_m": 115.28743123738266,
   "end_elevation_m": 116.61615958653846,
   "start_xy": [
    264033.137656953,
    213913.79635320316
   ],
   "end_xy": [
    264037.59873821796,
    213911.5383120241
   ]
  },
  "max_10m": {
   "gradient_pct": 21.242082702863456,
   "start_distance_m": 1768.0,
   "end_distance_m": 1778.0,
   "midpoint_distance_m": 1773.0,
   "start_elevation_m": 174.44249713972448,
   "end_elevation_m": 176.56670541001083,
   "start_xy": [
    264915.8787281267,
    214432.51943509525
   ],
   "end_xy": [
    264924.43835373194,
    214437.68981294322
   ]
  },
  "max_20m": {
   "gradient_pct": 18.45455280725048,
   "start_distance_m": 1759.0,
   "end_distance_m": 1779.0,
   "midpoint_distance_m": 1769.0,
   "start_elevation_m": 173.08438451552962,
   "end_elevation_m": 176.77529507697972,
   "start_xy": [
    264908.1748244249,
    214427.86649325665
   ],
   "end_xy": [
    264925.2943430321,
    214438.20680648086
   ]
  },
  "max_25m": {
   "gradient_pct": 18.25248868879737,
   "start_distance_m": 1754.0,
   "end_distance_m": 1779.0,
   "midpoint_distance_m": 1766.5,
   "start_elevation_m": 172.21217290478037,
   "end_elevation_m": 176.77529507697972,
   "start_xy": [
    264903.89487792394,
    214425.28152556854
   ],
   "end_xy": [
    264925.2943430321,
    214438.20680648086
   ]
  },
  "max_50m": {
   "gradient_pct": 17.194733631537503,
   "start_distance_m": 238.0,
   "end_distance_m": 288.0,
   "midpoint_distance_m": 263.0,
   "start_elevation_m": 80.3474499291399,
   "end_elevation_m": 88.94481674490865,
   "start_xy": [
    263700.6867436219,
    214005.021165801
   ],
   "end_xy": [
    263711.45033282944,
    213956.20799937524
   ]
  },
  "max_100m": {
   "gradient_pct": 14.479824434170197,
   "start_distance_m": 188.0,
   "end_distance_m": 288.0,
   "midpoint_distance_m": 238.0,
   "start_elevation_m": 74.46499231073845,
   "end_elevation_m": 88.94481674490865,
   "start_xy": [
    263671.8028929838,
    214044.31777374426
   ],
   "end_xy": [
    263711.45033282944,
    213956.20799937524
   ]
  }
 },
 "window_minima": {
  "min_5m": {
   "gradient_pct": -13.156358714084035,
   "start_distance_m": 3169.0,
   "end_distance_m": 3174.0,
   "midpoint_distance_m": 3171.5,
   "start_elevation_m": 265.8527521292147,
   "end_elevation_m": 265.1949341935105,
   "start_xy": [
    266121.98717174865,
    215145.08973656205
   ],
   "end_xy": [
    266126.3095461373,
    215147.60311579297
   ]
  },
  "min_10m": {
   "gradient_pct": -9.312879967594085,
   "start_distance_m": 3224.0,
   "end_distance_m": 3234.0,
   "midpoint_distance_m": 3229.0,
   "start_elevation_m": 266.2363835151886,
   "end_elevation_m": 265.3050955184292,
   "start_xy": [
    266169.532899946,
    215172.737578325
   ],
   "end_xy": [
    266178.1778372019,
    215177.76401189278
   ]
  },
  "min_20m": {
   "gradient_pct": -7.2706111179880395,
   "start_distance_m": 1407.0,
   "end_distance_m": 1427.0,
   "midpoint_distance_m": 1417.0,
   "start_elevation_m": 154.12889275885357,
   "end_elevation_m": 152.67477053525596,
   "start_xy": [
    264683.0939317018,
    214175.24502899576
   ],
   "end_xy": [
    264695.92396115,
    214190.58746209365
   ]
  },
  "min_25m": {
   "gradient_pct": -5.999625802706987,
   "start_distance_m": 1407.0,
   "end_distance_m": 1432.0,
   "midpoint_distance_m": 1419.5,
   "start_elevation_m": 154.12889275885357,
   "end_elevation_m": 152.62898630817682,
   "start_xy": [
    264683.0939317018,
    214175.24502899576
   ],
   "end_xy": [
    264699.1317614736,
    214194.42282562342
   ]
  },
  "min_50m": {
   "gradient_pct": -3.0924876909628267,
   "start_distance_m": 27.0,
   "end_distance_m": 77.0,
   "midpoint_distance_m": 52.0,
   "start_elevation_m": 72.4959835591592,
   "end_elevation_m": 70.94973971367779,
   "start_xy": [
    263707.0711404454,
    214191.18631054804
   ],
   "end_xy": [
    263685.7260047548,
    214145.97800968197
   ]
  },
  "min_100m": {
   "gradient_pct": -2.3042180732196442,
   "start_distance_m": 21.0,
   "end_distance_m": 121.0,
   "midpoint_distance_m": 71.0,
   "start_elevation_m": 72.69332397557628,
   "end_elevation_m": 70.38910590235663,
   "start_xy": [
    263709.5460447838,
    214196.6520987847
   ],
   "end_xy": [
    263666.3347304003,
    214106.48145101912
   ]
  }
 },
 "diagnostic_window_maxima": {
  "max_2m": {
   "gradient_pct": 43.39988713969234,
   "start_distance_m": 636.0,
   "end_distance_m": 638.0,
   "midpoint_distance_m": 637.0,
   "start_elevation_m": 115.74816184374461,
   "end_elevation_m": 116.61615958653846,
   "start_xy": [
    264035.8144623963,
    213912.44183795882
   ],
   "end_xy": [
    264037.59873821796,
    213911.5383120241
   ]
  },
  "max_3m": {
   "gradient_pct": 36.01083395081588,
   "start_distance_m": 635.0,
   "end_distance_m": 638.0,
   "midpoint_distance_m": 636.5,
   "start_elevation_m": 115.53583456801398,
   "end_elevation_m": 116.61615958653846,
   "start_xy": [
    264034.9221672756,
    213912.89329047193
   ],
   "end_xy": [
    264037.59873821796,
    213911.5383120241
   ]
  }
 },
 "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": {
  "structure_suppression": {
   "masked_fraction": 0.01,
   "windows_resited": [],
   "windows_unresolved": [],
   "minima_resited": [
    2.0,
    3.0,
    5.0,
    10.0,
    50.0,
    100.0
   ],
   "minima_unresolved": []
  },
  "texture_suppression": {
   "masked_fraction": 0.019,
   "windows_resited": [
    10.0,
    20.0,
    25.0,
    50.0,
    100.0
   ],
   "windows_unresolved": [],
   "minima_resited": [],
   "minima_unresolved": []
  },
  "texture_windows": {
   "rounds": 1,
   "windows_masked": [
    {
     "window_m": 25.0,
     "start_m": 583.0,
     "end_m": 608.0,
     "raw_pct": 20.42,
     "reason": "hump"
    },
    {
     "window_m": 20.0,
     "start_m": 583.0,
     "end_m": 603.0,
     "raw_pct": 20.84,
     "reason": "hump"
    }
   ],
   "advisory": [],
   "unresolved": [],
   "unstable": [
    {
     "window_m": 5.0,
     "start_m": 633.0,
     "end_m": 638.0,
     "raw_pct": 26.57,
     "reason": "short-step",
     "perturbations": [
      "phase+0.000/mask+0",
      "phase+0.333/mask+1",
      "phase+0.667/mask-1"
     ],
     "perturbation_reasons": [
      "short-step",
      "",
      ""
     ]
    }
   ]
  },
  "overhead_obstruction": {
   "obstruction_threshold_m": 2.0,
   "obstructed_fraction": 0.354,
   "obstruction_max_height_m": 20.12,
   "flagged_windows_m": [
    2,
    3,
    5,
    10,
    20,
    25,
    50,
    100
   ]
  },
  "excluded_ranges_m": [
   [
    0.0,
    20.0
   ],
   [
    581.0,
    610.0
   ],
   [
    1333.0,
    1338.0
   ],
   [
    1367.0,
    1372.0
   ]
  ],
  "review": [],
  "extent": [
   "descends_at_start"
  ]
 },
 "provenance": {
  "analysis_version": "0.1.0",
  "run_manifest": {
   "manifest_version": "1",
   "code_git_sha": "cd1381c557ec0196a6c481fc125290b249b285c2",
   "code_git_dirty": "true",
   "analysis_version": "0.1.0",
   "analysis_config_digest": "sha256:faa4beed0662d2f6",
   "python": "3.14.4",
   "numpy": "2.5.3",
   "rasterio": "1.5.1",
   "pyproj": "3.8.0",
   "laspy": "2.7.0",
   "shapely": "2.1.2",
   "pyosmium": "4.3.1",
   "libosmium": "2.23.1",
   "gdal": "3.12.4",
   "proj": "9.8.1",
   "run_id": "remeasure-260920-uk",
   "road_pbf": "batch-wales-chunk007.pbf",
   "region_key": "wales",
   "crs": "EPSG:27700",
   "elevation_provider_key": "wales",
   "authority": "os-open-roads",
   "registry_pbf": "wales-2026-08-11.osm.pbf"
  },
  "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/wales/dtm_1m/wg_del_21_263213_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_263214_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_263215_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_264213_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_264214_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_264215_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_265213_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_265214_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_265215_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_266213_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_266214_20220113dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_21_266215_20220113dtm.tif"
  ],
  "calculated_at": "2026-09-21T02:14:38+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "output/remeasure-260920/uk/batch-wales-chunk007.pbf",
  "osm_snapshot": "",
  "run_id": "remeasure-260920-uk",
  "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_21_263213_20220113dtm.tif",
   "wg_del_21_263214_20220113dtm.tif",
   "wg_del_21_263215_20220113dtm.tif",
   "wg_del_21_264213_20220113dtm.tif",
   "wg_del_21_264214_20220113dtm.tif",
   "wg_del_21_264215_20220113dtm.tif",
   "wg_del_21_265213_20220113dtm.tif",
   "wg_del_21_265214_20220113dtm.tif",
   "wg_del_21_265215_20220113dtm.tif",
   "wg_del_21_266213_20220113dtm.tif",
   "wg_del_21_266214_20220113dtm.tif",
   "wg_del_21_266215_20220113dtm.tif"
  ],
  "elevation_capture_dates": [
   "13-01-2022"
  ],
  "climb_origin": "discovered",
  "structure_own_ways": "none \u2014 the route carried no way list; own decks unmasked",
  "structure_mask_ranges_m": [
   [
    0.0,
    15.0
   ]
  ],
  "suppression_unstable": [
   5.0
  ],
  "carriageway": {
   "stations": 136,
   "stations_resolved": 136,
   "width_median_m": 4.0,
   "width_p10_m": 2.0,
   "width_min_m": 0.5,
   "width_max_m": 12.0,
   "bounded_share": 0.257,
   "unbounded_share": 0.743,
   "confidence_median": 0.0,
   "width_median_bounded_m": 2.75,
   "window_m": [
    1754.0,
    1779.0
   ],
   "width_at_max25_m": 3.25,
   "window_stations": 7,
   "single_track": false,
   "single_track_rule": "PROVISIONAL (2026-09-15): width_p10_m <= 3.0 m with bounded_share >= 0.6; recorded, not a rule",
   "status": "ok",
   "source": "dtm",
   "station_m": 25.0,
   "window_station_m": 5.0,
   "halfwidth_m": 6.0,
   "step_m": 0.25,
   "level_tol_m": 0.12,
   "break_min_m": 0.3,
   "stations_failed": 0,
   "hedge_to_hedge": {
    "stations": 136,
    "stations_resolved": 136,
    "width_median_m": 2.75,
    "width_p10_m": 1.25,
    "width_min_m": 0.5,
    "width_max_m": 10.75,
    "bounded_share": 0.971,
    "unbounded_share": 0.029,
    "confidence_median": 1.0,
    "width_median_bounded_m": 2.62,
    "window_m": [
     1754.0,
     1779.0
    ],
    "width_at_max25_m": 2.5,
    "window_stations": 7,
    "status": "ok",
    "source": "dsm",
    "station_m": 25.0,
    "window_station_m": 5.0,
    "halfwidth_m": 6.0,
    "step_m": 0.25,
    "level_tol_m": 0.5,
    "break_min_m": 0.3,
    "stations_failed": 0
   }
  },
  "remeasured": {
   "on": "2026-09-21",
   "why": "corpus re-measure 2026-09-21: a mask that exists today reaching a page published before it did; fallers only (Peter: fold the fallers)",
   "published_max25_pct": 20.92,
   "max25_pct": 18.25
  },
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing"
 },
 "area": {
  "place": "Ammanford",
  "county": "Sir Gaerfyrddin - Carmarthenshire"
 }
}