{
 "ocl_version": "0.1.0",
 "name": "Trefton Drive",
 "slug": "trefton-drive",
 "confidence": "A",
 "reported_claims": [],
 "ladder": [
  {
   "window_m": 2.0,
   "max_gradient_pct": 23.334754612477315,
   "diagnostic": true,
   "flags": [],
   "start_distance_m": 105.0,
   "end_distance_m": 107.0,
   "start_elevation_m": 11.52618430025405,
   "end_elevation_m": 11.992879392503596,
   "min_gradient_pct": -10.307509031223283
  },
  {
   "window_m": 3.0,
   "max_gradient_pct": 23.165871288802776,
   "diagnostic": true,
   "flags": [],
   "start_distance_m": 105.0,
   "end_distance_m": 108.0,
   "start_elevation_m": 11.52618430025405,
   "end_elevation_m": 12.221160438918133,
   "min_gradient_pct": -10.236566179500292
  },
  {
   "window_m": 5.0,
   "max_gradient_pct": 23.10665265034128,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 105.0,
   "end_distance_m": 110.0,
   "start_elevation_m": 11.52618430025405,
   "end_elevation_m": 12.681516932771114,
   "min_gradient_pct": -10.230784366512253
  },
  {
   "window_m": 10.0,
   "max_gradient_pct": 22.898832642168188,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 102.0,
   "end_distance_m": 112.0,
   "start_elevation_m": 10.842652788691353,
   "end_elevation_m": 13.132536052908172,
   "min_gradient_pct": -10.019300993156293
  },
  {
   "window_m": 20.0,
   "max_gradient_pct": 22.18526965661578,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 97.0,
   "end_distance_m": 117.0,
   "start_elevation_m": 9.766201229324336,
   "end_elevation_m": 14.203255160647492,
   "min_gradient_pct": -9.874498898495858
  },
  {
   "window_m": 25.0,
   "max_gradient_pct": 21.762405032557528,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 94.0,
   "end_distance_m": 119.0,
   "start_elevation_m": 9.169269438952501,
   "end_elevation_m": 14.609870697091882,
   "min_gradient_pct": -9.643322734106789
  },
  {
   "window_m": 50.0,
   "max_gradient_pct": 19.328853285974304,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 85.0,
   "end_distance_m": 135.0,
   "start_elevation_m": 7.667720566395601,
   "end_elevation_m": 17.332147209382754,
   "min_gradient_pct": -8.188458031081154
  },
  {
   "window_m": 100.0,
   "max_gradient_pct": 15.753790647426507,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 77.0,
   "end_distance_m": 177.0,
   "start_elevation_m": 6.723659912525582,
   "end_elevation_m": 22.47745055995209,
   "min_gradient_pct": -4.820342038584304
  }
 ],
 "shape": {
  "ascent_concentration": 0.582,
  "concentration_window_frac": 0.25,
  "longest_pitch_10pct_m": 107.0,
  "shape_class": "stepped"
 },
 "length_m": 770.387632280591,
 "start_elevation_m": 2.570958875005578,
 "end_elevation_m": 30.743568603634582,
 "endpoint_gain_m": 28.172609728629006,
 "overall_gradient_pct": 3.6569395130642444,
 "accumulated_ascent_m": 38.14458560033195,
 "window_maxima": {
  "max_5m": {
   "gradient_pct": 23.10665265034128,
   "start_distance_m": 105.0,
   "end_distance_m": 110.0,
   "midpoint_distance_m": 107.5,
   "start_elevation_m": 11.52618430025405,
   "end_elevation_m": 12.681516932771114,
   "start_xy": [
    337908.6277641595,
    4677405.094875604
   ],
   "end_xy": [
    337904.2317256801,
    4677402.712682143
   ]
  },
  "max_10m": {
   "gradient_pct": 22.898832642168188,
   "start_distance_m": 102.0,
   "end_distance_m": 112.0,
   "midpoint_distance_m": 107.0,
   "start_elevation_m": 10.842652788691353,
   "end_elevation_m": 13.132536052908172,
   "start_xy": [
    337911.2653872472,
    4677406.524191681
   ],
   "end_xy": [
    337902.47331028833,
    4677401.759804758
   ]
  },
  "max_20m": {
   "gradient_pct": 22.18526965661578,
   "start_distance_m": 97.0,
   "end_distance_m": 117.0,
   "midpoint_distance_m": 107.0,
   "start_elevation_m": 9.766201229324336,
   "end_elevation_m": 14.203255160647492,
   "start_xy": [
    337915.6614257266,
    4677408.906385142
   ],
   "end_xy": [
    337898.0772718089,
    4677399.377611297
   ]
  },
  "max_25m": {
   "gradient_pct": 21.762405032557528,
   "start_distance_m": 94.0,
   "end_distance_m": 119.0,
   "midpoint_distance_m": 106.5,
   "start_elevation_m": 9.169269438952501,
   "end_elevation_m": 14.609870697091882,
   "start_xy": [
    337918.2990488142,
    4677410.33570122
   ],
   "end_xy": [
    337896.31885641714,
    4677398.424733913
   ]
  },
  "max_50m": {
   "gradient_pct": 19.328853285974304,
   "start_distance_m": 85.0,
   "end_distance_m": 135.0,
   "midpoint_distance_m": 110.0,
   "start_elevation_m": 7.667720566395601,
   "end_elevation_m": 17.332147209382754,
   "start_xy": [
    337926.2119180772,
    4677414.62364945
   ],
   "end_xy": [
    337882.25153328304,
    4677390.801714836
   ]
  },
  "max_100m": {
   "gradient_pct": 15.753790647426507,
   "start_distance_m": 77.0,
   "end_distance_m": 177.0,
   "midpoint_distance_m": 127.0,
   "start_elevation_m": 6.723659912525582,
   "end_elevation_m": 22.47745055995209,
   "start_xy": [
    337933.2455796443,
    4677418.435158988
   ],
   "end_xy": [
    337845.32481005596,
    4677370.791289761
   ]
  }
 },
 "window_minima": {
  "min_5m": {
   "gradient_pct": -10.230784366512253,
   "start_distance_m": 384.0,
   "end_distance_m": 389.0,
   "midpoint_distance_m": 386.5,
   "start_elevation_m": 31.82447880596473,
   "end_elevation_m": 31.312939587639118,
   "start_xy": [
    337663.05303661147,
    4677272.680089545
   ],
   "end_xy": [
    337658.6465308692,
    4677270.31731424
   ]
  },
  "min_10m": {
   "gradient_pct": -10.019300993156293,
   "start_distance_m": 384.0,
   "end_distance_m": 394.0,
   "midpoint_distance_m": 389.0,
   "start_elevation_m": 31.82447880596473,
   "end_elevation_m": 30.8225487066491,
   "start_xy": [
    337663.05303661147,
    4677272.680089545
   ],
   "end_xy": [
    337654.2400251269,
    4677267.954538935
   ]
  },
  "min_20m": {
   "gradient_pct": -9.874498898495858,
   "start_distance_m": 381.0,
   "end_distance_m": 401.0,
   "midpoint_distance_m": 391.0,
   "start_elevation_m": 32.10612324546512,
   "end_elevation_m": 30.13122346576595,
   "start_xy": [
    337665.69694005686,
    4677274.097754729
   ],
   "end_xy": [
    337648.0709170877,
    4677264.646653508
   ]
  },
  "min_25m": {
   "gradient_pct": -9.643322734106789,
   "start_distance_m": 380.0,
   "end_distance_m": 405.0,
   "midpoint_distance_m": 392.5,
   "start_elevation_m": 32.19400281236159,
   "end_elevation_m": 29.78317212883489,
   "start_xy": [
    337666.5782412053,
    4677274.57030979
   ],
   "end_xy": [
    337644.5457124939,
    4677262.756433263
   ]
  },
  "min_50m": {
   "gradient_pct": -8.188458031081154,
   "start_distance_m": 372.0,
   "end_distance_m": 422.0,
   "midpoint_distance_m": 397.0,
   "start_elevation_m": 32.73423927693727,
   "end_elevation_m": 28.64001026139669,
   "start_xy": [
    337673.62865039293,
    4677278.350750278
   ],
   "end_xy": [
    337629.5635929701,
    4677254.722997225
   ]
  },
  "min_100m": {
   "gradient_pct": -4.820342038584304,
   "start_distance_m": 352.0,
   "end_distance_m": 452.0,
   "midpoint_distance_m": 402.0,
   "start_elevation_m": 32.988301961537275,
   "end_elevation_m": 28.16795992295297,
   "start_xy": [
    337691.2546733621,
    4677287.801851499
   ],
   "end_xy": [
    337603.09971533646,
    4677240.593758676
   ]
  }
 },
 "diagnostic_window_maxima": {
  "max_2m": {
   "gradient_pct": 23.334754612477315,
   "start_distance_m": 105.0,
   "end_distance_m": 107.0,
   "midpoint_distance_m": 106.0,
   "start_elevation_m": 11.52618430025405,
   "end_elevation_m": 11.992879392503596,
   "start_xy": [
    337908.6277641595,
    4677405.094875604
   ],
   "end_xy": [
    337906.8693487678,
    4677404.141998219
   ]
  },
  "max_3m": {
   "gradient_pct": 23.165871288802776,
   "start_distance_m": 105.0,
   "end_distance_m": 108.0,
   "midpoint_distance_m": 106.5,
   "start_elevation_m": 11.52618430025405,
   "end_elevation_m": 12.221160438918133,
   "start_xy": [
    337908.6277641595,
    4677405.094875604
   ],
   "end_xy": [
    337905.9901410719,
    4677403.665559527
   ]
  }
 },
 "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": {
  "review": [],
  "extent": [],
  "suggested_summit_cut_m": 623.0,
  "trailing_descent_m": 3.2
 },
 "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:26919",
  "elevation_resolution_m": 1.0,
  "elevation_tiles": [
   "data/cache/usa/ma-east/USGS_1M_19_x33y468_MA_CentralEastern_2021_B21.tif"
  ],
  "calculated_at": "2026-08-24T21:42:14+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/massachusetts-260822.osm.pbf",
  "osm_snapshot": "2026-08-21T20:21:11Z",
  "run_id": "redo-ma-2-260824",
  "elevation_provider": "USGS 3DEP (The National Map)",
  "elevation_licence": "Public domain \u2014 USGS 3DEP 1 m DEM, courtesy of the U.S. Geological Survey",
  "elevation_dataset": "USGS 3DEP 1 m DEM, MA_CentralEastern_2021_B21 (collected 2021)",
  "elevation_tile_ids": [
   "x33y468"
  ],
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 11.3% over 200 m (Terrain 50), gain 26.8 m over 730 m way. EXTENDED by graph walk: +0 segment(s) at base, +1 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. ADOPTED (NE wave 1, 2026-08-25): clean-steep. Wales dials per PRODUCTION 'US ADOPTION DIALS'.",
  "canopy_check": "unavailable \u2014 no surface model (DSM or point cloud) registered for this coverage",
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing.html"
 },
 "area": {
  "place": "Braintree Town",
  "county": "Massachusetts"
 }
}