{
 "ocl_version": "0.1.0",
 "name": "Ffordd Llwyn Du",
 "slug": "ffordd-llwyn-du",
 "ladder": [
  {
   "window_m": 2.0,
   "max_gradient_pct": 47.039968720625325,
   "diagnostic": true,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 1054.0,
   "end_distance_m": 1056.0,
   "start_elevation_m": 180.22296911215258,
   "end_elevation_m": 181.1637684865651,
   "min_gradient_pct": -26.73013992559312
  },
  {
   "window_m": 3.0,
   "max_gradient_pct": 41.86805578142412,
   "diagnostic": true,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 1058.0,
   "end_distance_m": 1061.0,
   "start_elevation_m": 181.43695342956676,
   "end_elevation_m": 182.69299510300948,
   "min_gradient_pct": -23.414843036286232
  },
  {
   "window_m": 5.0,
   "max_gradient_pct": 32.5340575460217,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 1058.0,
   "end_distance_m": 1063.0,
   "start_elevation_m": 181.43695342956676,
   "end_elevation_m": 183.06365630686784,
   "min_gradient_pct": -16.774584781629045
  },
  {
   "window_m": 10.0,
   "max_gradient_pct": 30.244710999064353,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 1052.0,
   "end_distance_m": 1062.0,
   "start_elevation_m": 179.8363273913044,
   "end_elevation_m": 182.86079849121083,
   "min_gradient_pct": -8.930070429099857
  },
  {
   "window_m": 20.0,
   "max_gradient_pct": 29.487525864422036,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 482.0,
   "end_distance_m": 502.0,
   "start_elevation_m": 87.01909194988203,
   "end_elevation_m": 92.91659712276643,
   "min_gradient_pct": -7.111710140548553
  },
  {
   "window_m": 25.0,
   "max_gradient_pct": 28.250351426492216,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 477.0,
   "end_distance_m": 502.0,
   "start_elevation_m": 85.85400926614338,
   "end_elevation_m": 92.91659712276643,
   "min_gradient_pct": -5.828799889587856
  },
  {
   "window_m": 50.0,
   "max_gradient_pct": 27.43686815820243,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 473.0,
   "end_distance_m": 523.0,
   "start_elevation_m": 84.77885042999404,
   "end_elevation_m": 98.49728450909525,
   "min_gradient_pct": -2.357574982033867
  },
  {
   "window_m": 100.0,
   "max_gradient_pct": 23.989104367206906,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 432.0,
   "end_distance_m": 532.0,
   "start_elevation_m": 76.06996806443452,
   "end_elevation_m": 100.05907243164143,
   "min_gradient_pct": 0.6163322058975496
  }
 ],
 "length_m": 1493.7636528296293,
 "start_elevation_m": 40.4765830914011,
 "end_elevation_m": 222.09517082238773,
 "endpoint_gain_m": 181.61858773098663,
 "overall_gradient_pct": 12.158455414746998,
 "accumulated_ascent_m": 187.5100843900711,
 "window_maxima": {
  "max_5m": {
   "gradient_pct": 32.5340575460217,
   "start_distance_m": 1058.0,
   "end_distance_m": 1063.0,
   "midpoint_distance_m": 1060.5,
   "start_elevation_m": 181.43695342956676,
   "end_elevation_m": 183.06365630686784,
   "start_xy": [
    281335.57154643175,
    369749.649134261
   ],
   "end_xy": [
    281340.4626950473,
    369748.6115094633
   ]
  },
  "max_10m": {
   "gradient_pct": 30.244710999064353,
   "start_distance_m": 1052.0,
   "end_distance_m": 1062.0,
   "midpoint_distance_m": 1057.0,
   "start_elevation_m": 179.8363273913044,
   "end_elevation_m": 182.86079849121083,
   "start_xy": [
    281329.89563691424,
    369751.4369147287
   ],
   "end_xy": [
    281339.4844653242,
    369748.8190344228
   ]
  },
  "max_20m": {
   "gradient_pct": 29.487525864422036,
   "start_distance_m": 482.0,
   "end_distance_m": 502.0,
   "midpoint_distance_m": 492.0,
   "start_elevation_m": 87.01909194988203,
   "end_elevation_m": 92.91659712276643,
   "start_xy": [
    280997.87954667135,
    369501.02577197144
   ],
   "end_xy": [
    281016.0808318066,
    369509.3151156985
   ]
  },
  "max_25m": {
   "gradient_pct": 28.250351426492216,
   "start_distance_m": 477.0,
   "end_distance_m": 502.0,
   "midpoint_distance_m": 489.5,
   "start_elevation_m": 85.85400926614338,
   "end_elevation_m": 92.91659712276643,
   "start_xy": [
    280993.32922538754,
    369498.9534360397
   ],
   "end_xy": [
    281016.0808318066,
    369509.3151156985
   ]
  },
  "max_50m": {
   "gradient_pct": 27.43686815820243,
   "start_distance_m": 473.0,
   "end_distance_m": 523.0,
   "midpoint_distance_m": 498.0,
   "start_elevation_m": 84.77885042999404,
   "end_elevation_m": 98.49728450909525,
   "start_xy": [
    280989.6889683605,
    369497.2955672943
   ],
   "end_xy": [
    281033.92277423525,
    369520.24111349747
   ]
  },
  "max_100m": {
   "gradient_pct": 23.989104367206906,
   "start_distance_m": 432.0,
   "end_distance_m": 532.0,
   "midpoint_distance_m": 482.0,
   "start_elevation_m": 76.06996806443452,
   "end_elevation_m": 100.05907243164143,
   "start_xy": [
    280951.252023656,
    369483.95728351804
   ],
   "end_xy": [
    281039.3141456118,
    369526.46540463914
   ]
  }
 },
 "window_minima": {
  "min_5m": {
   "gradient_pct": -16.774584781629045,
   "start_distance_m": 63.0,
   "end_distance_m": 68.0,
   "midpoint_distance_m": 65.5,
   "start_elevation_m": 41.20022671082604,
   "end_elevation_m": 40.361497471744585,
   "start_xy": [
    280610.6439547917,
    369437.4738843416
   ],
   "end_xy": [
    280614.9104023236,
    369440.0810716111
   ]
  },
  "min_10m": {
   "gradient_pct": -8.930070429099857,
   "start_distance_m": 321.0,
   "end_distance_m": 331.0,
   "midpoint_distance_m": 326.0,
   "start_elevation_m": 70.17469963258786,
   "end_elevation_m": 69.28169258967787,
   "start_xy": [
    280845.9222998978,
    369481.1987679365
   ],
   "end_xy": [
    280854.7767301754,
    369484.54467038705
   ]
  },
  "min_20m": {
   "gradient_pct": -7.111710140548553,
   "start_distance_m": 317.0,
   "end_distance_m": 337.0,
   "midpoint_distance_m": 327.0,
   "start_elevation_m": 70.34554767954252,
   "end_elevation_m": 68.92320565143281,
   "start_xy": [
    280842.84748287726,
    369478.64035040024
   ],
   "end_xy": [
    280860.77260557655,
    369484.7671072869
   ]
  },
  "min_25m": {
   "gradient_pct": -5.828799889587856,
   "start_distance_m": 314.0,
   "end_distance_m": 339.0,
   "midpoint_distance_m": 326.5,
   "start_elevation_m": 70.35819855411172,
   "end_elevation_m": 68.90099858171476,
   "start_xy": [
    280840.54137011187,
    369476.721537248
   ],
   "end_xy": [
    280862.54916219064,
    369483.975859
   ]
  },
  "min_50m": {
   "gradient_pct": -2.357574982033867,
   "start_distance_m": 308.0,
   "end_distance_m": 358.0,
   "midpoint_distance_m": 333.0,
   "start_elevation_m": 70.31862795227462,
   "end_elevation_m": 69.13984046125769,
   "start_xy": [
    280835.92914458096,
    369472.8839109436
   ],
   "end_xy": [
    280878.8508895729,
    369474.21605959866
   ]
  },
  "min_100m": {
   "gradient_pct": 0.6163322058975496,
   "start_distance_m": 0.0,
   "end_distance_m": 100.0,
   "midpoint_distance_m": 50.0,
   "start_elevation_m": 40.4765830914011,
   "end_elevation_m": 41.09291529729865,
   "start_xy": [
    280549.684,
    369423.083
   ],
   "end_xy": [
    280643.8462208042,
    369452.1311811316
   ]
  }
 },
 "diagnostic_window_maxima": {
  "max_2m": {
   "gradient_pct": 47.039968720625325,
   "start_distance_m": 1054.0,
   "end_distance_m": 1056.0,
   "midpoint_distance_m": 1055.0,
   "start_elevation_m": 180.22296911215258,
   "end_elevation_m": 181.1637684865651,
   "start_xy": [
    281331.6733692852,
    369750.5205809373
   ],
   "end_xy": [
    281333.6150869856,
    369750.0641841801
   ]
  },
  "max_3m": {
   "gradient_pct": 41.86805578142412,
   "start_distance_m": 1058.0,
   "end_distance_m": 1061.0,
   "midpoint_distance_m": 1059.5,
   "start_elevation_m": 181.43695342956676,
   "end_elevation_m": 182.69299510300948,
   "start_xy": [
    281335.57154643175,
    369749.649134261
   ],
   "end_xy": [
    281338.5062356011,
    369749.0265593824
   ]
  }
 },
 "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": 0.313,
   "obstruction_max_height_m": 21.92,
   "flagged_windows_m": [
    2,
    3,
    5,
    10
   ]
  },
  "review": [],
  "extent": [
   "may_continue_beyond_end"
  ]
 },
 "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/wales/dtm_1m/wg_del_12_280369_20210307dtm.tif",
   "data/cache/wales/dtm_1m/wg_del_12_281369_20210307dtm.tif"
  ],
  "calculated_at": "2026-08-12T09:10:21+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_12_280369_20210307dtm.tif",
   "wg_del_12_281369_20210307dtm.tif"
  ],
  "elevation_capture_dates": [
   "07-03-2021"
  ],
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 22.4% over 200 m (Terrain 50), gain 172.6 m over 1358 m way. EXTENDED by graph walk: +0 segment(s) at base, +2 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."
 },
 "area": {
  "place": "Pentre'r Felin",
  "county": "Conwy - Conwy"
 },
 "reported_claims": [],
 "confidence": "B",
 "shape": {
  "ascent_concentration": 0.382,
  "concentration_window_frac": 0.25,
  "longest_pitch_10pct_m": 374.0,
  "shape_class": "sustained"
 }
}