{
 "ocl_version": "0.1.0",
 "name": "Snake Road",
 "slug": "snake-road-3",
 "confidence": "A",
 "reported_claims": [],
 "ladder": [
  {
   "window_m": 2.0,
   "max_gradient_pct": 10.332028572506147,
   "diagnostic": true,
   "flags": [],
   "start_distance_m": 2933.0,
   "end_distance_m": 2935.0,
   "start_elevation_m": 377.9139619827106,
   "end_elevation_m": 378.1206025541607,
   "min_gradient_pct": 0.0500974959152245
  },
  {
   "window_m": 3.0,
   "max_gradient_pct": 9.834013312924602,
   "diagnostic": true,
   "flags": [],
   "start_distance_m": 2932.0,
   "end_distance_m": 2935.0,
   "start_elevation_m": 377.825582154773,
   "end_elevation_m": 378.1206025541607,
   "min_gradient_pct": 0.32914059457975026
  },
  {
   "window_m": 5.0,
   "max_gradient_pct": 9.194123892211792,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 2932.0,
   "end_distance_m": 2937.0,
   "start_elevation_m": 377.825582154773,
   "end_elevation_m": 378.28528834938356,
   "min_gradient_pct": 1.2076597312403692
  },
  {
   "window_m": 10.0,
   "max_gradient_pct": 8.658907372841895,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 2931.0,
   "end_distance_m": 2941.0,
   "start_elevation_m": 377.74673788754876,
   "end_elevation_m": 378.61262862483295,
   "min_gradient_pct": 1.7529372142655575
  },
  {
   "window_m": 20.0,
   "max_gradient_pct": 8.306084174571708,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 3237.0,
   "end_distance_m": 3257.0,
   "start_elevation_m": 399.5323780368458,
   "end_elevation_m": 401.1935948717601,
   "min_gradient_pct": 1.7797798695002598
  },
  {
   "window_m": 25.0,
   "max_gradient_pct": 8.221139284532228,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 3231.0,
   "end_distance_m": 3256.0,
   "start_elevation_m": 399.0638011804674,
   "end_elevation_m": 401.11908600160046,
   "min_gradient_pct": 1.8449442136006837
  },
  {
   "window_m": 50.0,
   "max_gradient_pct": 8.041945794072149,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 3224.0,
   "end_distance_m": 3274.0,
   "start_elevation_m": 398.5078411639388,
   "end_elevation_m": 402.52881406097487,
   "min_gradient_pct": 1.9970409202941255
  },
  {
   "window_m": 100.0,
   "max_gradient_pct": 7.971477645104187,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 3182.0,
   "end_distance_m": 3282.0,
   "start_elevation_m": 395.1966476295472,
   "end_elevation_m": 403.1681252746514,
   "min_gradient_pct": 2.1556492829015497
  }
 ],
 "shape": {
  "ascent_concentration": 0.281,
  "concentration_window_frac": 0.25,
  "longest_pitch_10pct_m": 0.0,
  "shape_class": "sustained"
 },
 "length_m": 5104.958059224632,
 "start_elevation_m": 181.40077583080893,
 "end_elevation_m": 506.0111746770628,
 "endpoint_gain_m": 324.6103988462539,
 "overall_gradient_pct": 6.358728026368103,
 "accumulated_ascent_m": 324.61807721256474,
 "window_maxima": {
  "max_5m": {
   "gradient_pct": 9.194123892211792,
   "start_distance_m": 2932.0,
   "end_distance_m": 2937.0,
   "midpoint_distance_m": 2934.5,
   "start_elevation_m": 377.825582154773,
   "end_elevation_m": 378.28528834938356,
   "start_xy": [
    407054.22373904666,
    393208.20921852253
   ],
   "end_xy": [
    407055.2373662909,
    393203.3130404406
   ]
  },
  "max_10m": {
   "gradient_pct": 8.658907372841895,
   "start_distance_m": 2931.0,
   "end_distance_m": 2941.0,
   "midpoint_distance_m": 2936.0,
   "start_elevation_m": 377.74673788754876,
   "end_elevation_m": 378.61262862483295,
   "start_xy": [
    407054.02101359784,
    393209.1884541389
   ],
   "end_xy": [
    407056.01822497445,
    393199.39450100163
   ]
  },
  "max_20m": {
   "gradient_pct": 8.306084174571708,
   "start_distance_m": 3237.0,
   "end_distance_m": 3257.0,
   "midpoint_distance_m": 3247.0,
   "start_elevation_m": 399.5323780368458,
   "end_elevation_m": 401.1935948717601,
   "start_xy": [
    407050.5993261811,
    392920.30994360306
   ],
   "end_xy": [
    407062.0718051882,
    392903.92820812034
   ]
  },
  "max_25m": {
   "gradient_pct": 8.221139284532228,
   "start_distance_m": 3231.0,
   "end_distance_m": 3256.0,
   "midpoint_distance_m": 3243.5,
   "start_elevation_m": 399.0638011804674,
   "end_elevation_m": 401.11908600160046,
   "start_xy": [
    407047.2208208665,
    392925.2683407069
   ],
   "end_xy": [
    407061.4948238868,
    392904.74496547587
   ]
  },
  "max_50m": {
   "gradient_pct": 8.041945794072149,
   "start_distance_m": 3224.0,
   "end_distance_m": 3274.0,
   "midpoint_distance_m": 3249.0,
   "start_elevation_m": 398.5078411639388,
   "end_elevation_m": 402.52881406097487,
   "start_xy": [
    407043.2792313328,
    392931.053137328
   ],
   "end_xy": [
    407071.8804873122,
    392890.0433330763
   ]
  },
  "max_100m": {
   "gradient_pct": 7.971477645104187,
   "start_distance_m": 3182.0,
   "end_distance_m": 3282.0,
   "midpoint_distance_m": 3232.0,
   "start_elevation_m": 395.1966476295472,
   "end_elevation_m": 403.1681252746514,
   "start_xy": [
    407020.8504158915,
    392966.4568662991
   ],
   "end_xy": [
    407076.4963377235,
    392883.50927423197
   ]
  }
 },
 "window_minima": {
  "min_5m": {
   "gradient_pct": 1.2076597312403692,
   "start_distance_m": 767.0,
   "end_distance_m": 772.0,
   "midpoint_distance_m": 769.5,
   "start_elevation_m": 231.6010394742424,
   "end_elevation_m": 231.66142246080443,
   "start_xy": [
    405622.66946385463,
    394342.5383772887
   ],
   "end_xy": [
    405627.23462793103,
    394340.540367498
   ]
  },
  "min_10m": {
   "gradient_pct": 1.7529372142655575,
   "start_distance_m": 4965.0,
   "end_distance_m": 4975.0,
   "midpoint_distance_m": 4970.0,
   "start_elevation_m": 502.6571946820048,
   "end_elevation_m": 502.83248840343134,
   "start_xy": [
    408444.83503765333,
    392875.3664492213
   ],
   "end_xy": [
    408452.9053999138,
    392881.24576016946
   ]
  },
  "min_20m": {
   "gradient_pct": 1.7797798695002598,
   "start_distance_m": 4965.0,
   "end_distance_m": 4985.0,
   "midpoint_distance_m": 4975.0,
   "start_elevation_m": 502.6571946820048,
   "end_elevation_m": 503.01315065590484,
   "start_xy": [
    408444.83503765333,
    392875.3664492213
   ],
   "end_xy": [
    408461.21548132587,
    392886.80836270103
   ]
  },
  "min_25m": {
   "gradient_pct": 1.8449442136006837,
   "start_distance_m": 4960.0,
   "end_distance_m": 4985.0,
   "midpoint_distance_m": 4972.5,
   "start_elevation_m": 502.55191460250467,
   "end_elevation_m": 503.01315065590484,
   "start_xy": [
    408441.0300160318,
    392872.1227151909
   ],
   "end_xy": [
    408461.21548132587,
    392886.80836270103
   ]
  },
  "min_50m": {
   "gradient_pct": 1.9970409202941255,
   "start_distance_m": 4939.0,
   "end_distance_m": 4989.0,
   "midpoint_distance_m": 4964.0,
   "start_elevation_m": 502.1129784898026,
   "end_elevation_m": 503.11149894994963,
   "start_xy": [
    408425.0560092912,
    392858.491487762
   ],
   "end_xy": [
    408464.5395138907,
    392889.03340371366
   ]
  },
  "min_100m": {
   "gradient_pct": 2.1556492829015497,
   "start_distance_m": 4940.0,
   "end_distance_m": 5040.0,
   "midpoint_distance_m": 4990.0,
   "start_elevation_m": 502.13761965258874,
   "end_elevation_m": 504.2932689354903,
   "start_xy": [
    408425.8099295459,
    392859.14777906926
   ],
   "end_xy": [
    408510.78781412344,
    392909.78099865664
   ]
  }
 },
 "diagnostic_window_maxima": {
  "max_2m": {
   "gradient_pct": 10.332028572506147,
   "start_distance_m": 2933.0,
   "end_distance_m": 2935.0,
   "midpoint_distance_m": 2934.0,
   "start_elevation_m": 377.9139619827106,
   "end_elevation_m": 378.1206025541607,
   "start_xy": [
    407054.4264644955,
    393207.22998290614
   ],
   "end_xy": [
    407054.8319153932,
    393205.27151167335
   ]
  },
  "max_3m": {
   "gradient_pct": 9.834013312924602,
   "start_distance_m": 2932.0,
   "end_distance_m": 2935.0,
   "midpoint_distance_m": 2933.5,
   "start_elevation_m": 377.825582154773,
   "end_elevation_m": 378.1206025541607,
   "start_xy": [
    407054.22373904666,
    393208.20921852253
   ],
   "end_xy": [
    407054.8319153932,
    393205.27151167335
   ]
  }
 },
 "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": 0.001,
   "obstruction_max_height_m": 6.29,
   "flagged_windows_m": []
  },
  "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/SK0090.tif",
   "data/cache/england/bulk_dtm_1m/SK0590.tif"
  ],
  "calculated_at": "2026-08-15T18:54:24+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/england-2026-08-12-roads.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",
  "elevation_tile_ids": [
   "SK0090.tif",
   "SK0590.tif"
  ],
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 7.5% over 200 m (Terrain 50), gain 52.5 m over 823 m way. EXTENDED by graph walk: +5 segment(s) at base, +1 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 1 overlapping proposal(s): snake-road-2"
 },
 "area": {
  "place": "Ramsley Clough",
  "county": "Derbyshire"
 }
}