{
 "ocl_version": "0.1.0",
 "name": "Chestnut Hill Road",
 "slug": "chestnut-hill-road",
 "confidence": "B",
 "reported_claims": [],
 "ladder": [
  {
   "window_m": 2.0,
   "max_gradient_pct": 36.163849821474514,
   "diagnostic": true,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 169.0,
   "end_distance_m": 171.0,
   "start_elevation_m": 469.98145180112283,
   "end_elevation_m": 470.7047287975523,
   "min_gradient_pct": -2.465160500713637
  },
  {
   "window_m": 3.0,
   "max_gradient_pct": 34.52404756881909,
   "diagnostic": true,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 169.0,
   "end_distance_m": 172.0,
   "start_elevation_m": 469.98145180112283,
   "end_elevation_m": 471.0171732281874,
   "min_gradient_pct": -2.372898757461902
  },
  {
   "window_m": 5.0,
   "max_gradient_pct": 32.61635783860811,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 168.0,
   "end_distance_m": 173.0,
   "start_elevation_m": 469.6807814451829,
   "end_elevation_m": 471.3115993371133,
   "min_gradient_pct": -2.0887275959819362
  },
  {
   "window_m": 10.0,
   "max_gradient_pct": 28.888381315142055,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 163.0,
   "end_distance_m": 173.0,
   "start_elevation_m": 468.4227612055991,
   "end_elevation_m": 471.3115993371133,
   "min_gradient_pct": 1.1807947241004513
  },
  {
   "window_m": 20.0,
   "max_gradient_pct": 24.15645786124486,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 154.0,
   "end_distance_m": 174.0,
   "start_elevation_m": 466.71874292411917,
   "end_elevation_m": 471.55003449636814,
   "min_gradient_pct": 1.8647207435680002
  },
  {
   "window_m": 25.0,
   "max_gradient_pct": 22.974537065318827,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 149.0,
   "end_distance_m": 174.0,
   "start_elevation_m": 465.80640023003843,
   "end_elevation_m": 471.55003449636814,
   "min_gradient_pct": 2.1831073804683
  },
  {
   "window_m": 50.0,
   "max_gradient_pct": 21.325667360234092,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 124.0,
   "end_distance_m": 174.0,
   "start_elevation_m": 460.8872008162511,
   "end_elevation_m": 471.55003449636814,
   "min_gradient_pct": 3.3578760327147847
  },
  {
   "window_m": 100.0,
   "max_gradient_pct": 18.96680240712209,
   "diagnostic": false,
   "flags": [
    "canopy_or_structure"
   ],
   "start_distance_m": 76.0,
   "end_distance_m": 176.0,
   "start_elevation_m": 452.88089633599657,
   "end_elevation_m": 471.84769874311866,
   "min_gradient_pct": 5.322163833699506
  }
 ],
 "shape": {
  "ascent_concentration": 0.338,
  "concentration_window_frac": 0.25,
  "longest_pitch_10pct_m": 190.0,
  "shape_class": "sustained"
 },
 "length_m": 660.9999999998427,
 "start_elevation_m": 445.01440310886204,
 "end_elevation_m": 529.0044943822724,
 "endpoint_gain_m": 83.99009127341031,
 "overall_gradient_pct": 12.706519103393388,
 "accumulated_ascent_m": 84.1008476126251,
 "window_maxima": {
  "max_5m": {
   "gradient_pct": 32.61635783860811,
   "start_distance_m": 168.0,
   "end_distance_m": 173.0,
   "midpoint_distance_m": 170.5,
   "start_elevation_m": 469.6807814451829,
   "end_elevation_m": 471.3115993371133,
   "start_xy": [
    650305.3806266632,
    4670520.000085338
   ],
   "end_xy": [
    650306.1706571846,
    4670515.062894677
   ]
  },
  "max_10m": {
   "gradient_pct": 28.888381315142055,
   "start_distance_m": 163.0,
   "end_distance_m": 173.0,
   "midpoint_distance_m": 168.0,
   "start_elevation_m": 468.4227612055991,
   "end_elevation_m": 471.3115993371133,
   "start_xy": [
    650304.5896212048,
    4670524.937119436
   ],
   "end_xy": [
    650306.1706571846,
    4670515.062894677
   ]
  },
  "max_20m": {
   "gradient_pct": 24.15645786124486,
   "start_distance_m": 154.0,
   "end_distance_m": 174.0,
   "midpoint_distance_m": 164.0,
   "start_elevation_m": 466.71874292411917,
   "end_elevation_m": 471.55003449636814,
   "start_xy": [
    650303.1666577959,
    4670533.823916701
   ],
   "end_xy": [
    650306.3287250058,
    4670514.075466419
   ]
  },
  "max_25m": {
   "gradient_pct": 22.974537065318827,
   "start_distance_m": 149.0,
   "end_distance_m": 174.0,
   "midpoint_distance_m": 161.5,
   "start_elevation_m": 465.80640023003843,
   "end_elevation_m": 471.55003449636814,
   "start_xy": [
    650302.1254561945,
    4670538.694868052
   ],
   "end_xy": [
    650306.3287250058,
    4670514.075466419
   ]
  },
  "max_50m": {
   "gradient_pct": 21.325667360234092,
   "start_distance_m": 124.0,
   "end_distance_m": 174.0,
   "midpoint_distance_m": 149.0,
   "start_elevation_m": 460.8872008162511,
   "end_elevation_m": 471.55003449636814,
   "start_xy": [
    650292.7743479235,
    4670561.8801376335
   ],
   "end_xy": [
    650306.3287250058,
    4670514.075466419
   ]
  },
  "max_100m": {
   "gradient_pct": 18.96680240712209,
   "start_distance_m": 76.0,
   "end_distance_m": 176.0,
   "midpoint_distance_m": 126.0,
   "start_elevation_m": 452.88089633599657,
   "end_elevation_m": 471.84769874311866,
   "start_xy": [
    650270.7695595748,
    4670604.451004185
   ],
   "end_xy": [
    650306.6456816513,
    4670512.100741837
   ]
  }
 },
 "window_minima": {
  "min_5m": {
   "gradient_pct": -2.0887275959819362,
   "start_distance_m": 1.0,
   "end_distance_m": 6.0,
   "midpoint_distance_m": 3.5,
   "start_elevation_m": 445.00808314944635,
   "end_elevation_m": 444.90364676964725,
   "start_xy": [
    650239.1012000624,
    4670672.429568511
   ],
   "end_xy": [
    650241.2030832771,
    4670667.892820588
   ]
  },
  "min_10m": {
   "gradient_pct": 1.1807947241004513,
   "start_distance_m": 651.0,
   "end_distance_m": 661.0,
   "midpoint_distance_m": 656.0,
   "start_elevation_m": 528.8864149098623,
   "end_elevation_m": 529.0044943822724,
   "start_xy": [
    650511.8176634894,
    4670145.777847994
   ],
   "end_xy": [
    650513.5057263058,
    4670135.921356324
   ]
  },
  "min_20m": {
   "gradient_pct": 1.8647207435680002,
   "start_distance_m": 641.0,
   "end_distance_m": 661.0,
   "midpoint_distance_m": 651.0,
   "start_elevation_m": 528.6315502335588,
   "end_elevation_m": 529.0044943822724,
   "start_xy": [
    650510.1298453738,
    4670155.634381429
   ],
   "end_xy": [
    650513.5057263058,
    4670135.921356324
   ]
  },
  "min_25m": {
   "gradient_pct": 2.1831073804683,
   "start_distance_m": 636.0,
   "end_distance_m": 661.0,
   "midpoint_distance_m": 648.5,
   "start_elevation_m": 528.4587175371553,
   "end_elevation_m": 529.0044943822724,
   "start_xy": [
    650509.2858035564,
    4670160.562625405
   ],
   "end_xy": [
    650513.5057263058,
    4670135.921356324
   ]
  },
  "min_50m": {
   "gradient_pct": 3.3578760327147847,
   "start_distance_m": 611.0,
   "end_distance_m": 661.0,
   "midpoint_distance_m": 636.0,
   "start_elevation_m": 527.325556365915,
   "end_elevation_m": 529.0044943822724,
   "start_xy": [
    650505.4474392477,
    4670185.265423893
   ],
   "end_xy": [
    650513.5057263058,
    4670135.921356324
   ]
  },
  "min_100m": {
   "gradient_pct": 5.322163833699506,
   "start_distance_m": 561.0,
   "end_distance_m": 661.0,
   "midpoint_distance_m": 611.0,
   "start_elevation_m": 523.6823305485728,
   "end_elevation_m": 529.0044943822724,
   "start_xy": [
    650498.1412711284,
    4670234.726830972
   ],
   "end_xy": [
    650513.5057263058,
    4670135.921356324
   ]
  }
 },
 "diagnostic_window_maxima": {
  "max_2m": {
   "gradient_pct": 36.163849821474514,
   "start_distance_m": 169.0,
   "end_distance_m": 171.0,
   "midpoint_distance_m": 170.0,
   "start_elevation_m": 469.98145180112283,
   "end_elevation_m": 470.7047287975523,
   "start_xy": [
    650305.5386945147,
    4670519.0126570845
   ],
   "end_xy": [
    650305.8546761927,
    4670517.037775936
   ]
  },
  "max_3m": {
   "gradient_pct": 34.52404756881909,
   "start_distance_m": 169.0,
   "end_distance_m": 172.0,
   "midpoint_distance_m": 170.5,
   "start_elevation_m": 469.98145180112283,
   "end_elevation_m": 471.0171732281874,
   "start_xy": [
    650305.5386945147,
    4670519.0126570845
   ],
   "end_xy": [
    650306.0127439952,
    4670516.050347675
   ]
  }
 },
 "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": 0.757,
   "obstruction_max_height_m": 30.04,
   "flagged_windows_m": [
    2,
    3,
    5,
    10,
    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:26918",
  "elevation_resolution_m": 1.0,
  "elevation_tiles": [
   "data/cache/usa/ma/USGS_1M_18_x65y468_MA_Western_B24.tif"
  ],
  "calculated_at": "2026-09-03T22:40:20+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": "extent-trim-v2-260903",
  "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_Western_B24 (collected 2023-24)",
  "elevation_tile_ids": [
   "x65y468"
  ],
  "route_cut_m": 661.0,
  "climb_origin": "discovered",
  "canopy_source": {
   "kind": "ept_corridor_max_return",
   "ept_source": "https://usgs-lidar-public.s3-us-west-2.amazonaws.com/USGS_LPC_MA_ME_MA_QL2_UTM18_L1_2015_LAS_2018",
   "ept_crs": "EPSG:3857",
   "station_coverage": 1.0,
   "cell_ground_m": 1.0,
   "nodes_failed": 0
  },
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing.html"
 },
 "area": {
  "place": "Monterey",
  "county": "Massachusetts"
 }
}