{
 "ocl_version": "0.1.0",
 "name": "Grange Hall Road",
 "slug": "grange-hall-road",
 "confidence": "A",
 "reported_claims": [],
 "ladder": [
  {
   "window_m": 2.0,
   "max_gradient_pct": 16.55920914485023,
   "diagnostic": true,
   "flags": [],
   "start_distance_m": 1066.0,
   "end_distance_m": 1068.0,
   "start_elevation_m": 472.1717036109368,
   "end_elevation_m": 472.5028877938338,
   "min_gradient_pct": -1.0254256811492724
  },
  {
   "window_m": 3.0,
   "max_gradient_pct": 16.313676160920448,
   "diagnostic": true,
   "flags": [],
   "start_distance_m": 1065.0,
   "end_distance_m": 1068.0,
   "start_elevation_m": 472.0134775090062,
   "end_elevation_m": 472.5028877938338,
   "min_gradient_pct": -0.8797589320124644
  },
  {
   "window_m": 5.0,
   "max_gradient_pct": 15.485780540484484,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 1065.0,
   "end_distance_m": 1070.0,
   "start_elevation_m": 472.0134775090062,
   "end_elevation_m": 472.7877665360304,
   "min_gradient_pct": -0.9187259432962946
  },
  {
   "window_m": 10.0,
   "max_gradient_pct": 15.324403260366921,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 1065.0,
   "end_distance_m": 1075.0,
   "start_elevation_m": 472.0134775090062,
   "end_elevation_m": 473.54591783504287,
   "min_gradient_pct": -0.7196024098016096
  },
  {
   "window_m": 20.0,
   "max_gradient_pct": 15.10252909368944,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 1065.0,
   "end_distance_m": 1085.0,
   "start_elevation_m": 472.0134775090062,
   "end_elevation_m": 475.03398332774407,
   "min_gradient_pct": -0.40937474013105657
  },
  {
   "window_m": 25.0,
   "max_gradient_pct": 14.917881845141892,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 1064.0,
   "end_distance_m": 1089.0,
   "start_elevation_m": 471.876695034329,
   "end_elevation_m": 475.60616549561445,
   "min_gradient_pct": -0.2889742074503374
  },
  {
   "window_m": 50.0,
   "max_gradient_pct": 14.446899354286302,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 1051.0,
   "end_distance_m": 1101.0,
   "start_elevation_m": 470.0900917139359,
   "end_elevation_m": 477.31354139107907,
   "min_gradient_pct": 0.37801893949392706
  },
  {
   "window_m": 100.0,
   "max_gradient_pct": 13.634274403447876,
   "diagnostic": false,
   "flags": [],
   "start_distance_m": 2045.0,
   "end_distance_m": 2145.0,
   "start_elevation_m": 547.907457249504,
   "end_elevation_m": 561.5417316529519,
   "min_gradient_pct": 1.8546002889026454
  }
 ],
 "shape": {
  "ascent_concentration": 0.321,
  "concentration_window_frac": 0.25,
  "longest_pitch_10pct_m": 366.0,
  "shape_class": "sustained"
 },
 "length_m": 2281.2384499692507,
 "start_elevation_m": 363.56219061767337,
 "end_elevation_m": 573.6329227124057,
 "endpoint_gain_m": 210.07073209473236,
 "overall_gradient_pct": 9.208626660556417,
 "accumulated_ascent_m": 210.1617991675501,
 "window_maxima": {
  "max_5m": {
   "gradient_pct": 15.485780540484484,
   "start_distance_m": 1065.0,
   "end_distance_m": 1070.0,
   "midpoint_distance_m": 1067.5,
   "start_elevation_m": 472.0134775090062,
   "end_elevation_m": 472.7877665360304,
   "start_xy": [
    650999.6583112692,
    4702255.734168399
   ],
   "end_xy": [
    651002.9353507253,
    4702251.957792834
   ]
  },
  "max_10m": {
   "gradient_pct": 15.324403260366921,
   "start_distance_m": 1065.0,
   "end_distance_m": 1075.0,
   "midpoint_distance_m": 1070.0,
   "start_elevation_m": 472.0134775090062,
   "end_elevation_m": 473.54591783504287,
   "start_xy": [
    650999.6583112692,
    4702255.734168399
   ],
   "end_xy": [
    651006.2947086917,
    4702248.254709419
   ]
  },
  "max_20m": {
   "gradient_pct": 15.10252909368944,
   "start_distance_m": 1065.0,
   "end_distance_m": 1085.0,
   "midpoint_distance_m": 1075.0,
   "start_elevation_m": 472.0134775090062,
   "end_elevation_m": 475.03398332774407,
   "start_xy": [
    650999.6583112692,
    4702255.734168399
   ],
   "end_xy": [
    651013.0390019176,
    4702240.871315289
   ]
  },
  "max_25m": {
   "gradient_pct": 14.917881845141892,
   "start_distance_m": 1064.0,
   "end_distance_m": 1089.0,
   "midpoint_distance_m": 1076.5,
   "start_elevation_m": 471.876695034329,
   "end_elevation_m": 475.60616549561445,
   "start_xy": [
    650999.0029033781,
    4702256.489443512
   ],
   "end_xy": [
    651015.7367192081,
    4702237.9179576365
   ]
  },
  "max_50m": {
   "gradient_pct": 14.446899354286302,
   "start_distance_m": 1051.0,
   "end_distance_m": 1101.0,
   "midpoint_distance_m": 1076.0,
   "start_elevation_m": 470.0900917139359,
   "end_elevation_m": 477.31354139107907,
   "start_xy": [
    650990.4826007923,
    4702266.308019979
   ],
   "end_xy": [
    651023.8298710792,
    4702229.05788468
   ]
  },
  "max_100m": {
   "gradient_pct": 13.634274403447876,
   "start_distance_m": 2045.0,
   "end_distance_m": 2145.0,
   "midpoint_distance_m": 2095.0,
   "start_elevation_m": 547.907457249504,
   "end_elevation_m": 561.5417316529519,
   "start_xy": [
    651785.7752608218,
    4701738.647463293
   ],
   "end_xy": [
    651864.7916169558,
    4701677.357916751
   ]
  }
 },
 "window_minima": {
  "min_5m": {
   "gradient_pct": -0.9187259432962946,
   "start_distance_m": 1438.0,
   "end_distance_m": 1443.0,
   "midpoint_distance_m": 1440.5,
   "start_elevation_m": 499.94905155079385,
   "end_elevation_m": 499.90311525362904,
   "start_xy": [
    651260.1756599181,
    4701994.68866143
   ],
   "end_xy": [
    651264.8485135195,
    4701992.910383342
   ]
  },
  "min_10m": {
   "gradient_pct": -0.7196024098016096,
   "start_distance_m": 1438.0,
   "end_distance_m": 1448.0,
   "midpoint_distance_m": 1443.0,
   "start_elevation_m": 499.94905155079385,
   "end_elevation_m": 499.8770913098137,
   "start_xy": [
    651260.1756599181,
    4701994.68866143
   ],
   "end_xy": [
    651269.5768094903,
    4701991.284585933
   ]
  },
  "min_20m": {
   "gradient_pct": -0.40937474013105657,
   "start_distance_m": 1431.0,
   "end_distance_m": 1451.0,
   "midpoint_distance_m": 1441.0,
   "start_elevation_m": 499.955001605383,
   "end_elevation_m": 499.8731266573568,
   "start_xy": [
    651253.6400522838,
    4701997.195817757
   ],
   "end_xy": [
    651272.4137870729,
    4701990.309107488
   ]
  },
  "min_25m": {
   "gradient_pct": -0.2889742074503374,
   "start_distance_m": 1426.0,
   "end_distance_m": 1451.0,
   "midpoint_distance_m": 1438.5,
   "start_elevation_m": 499.9453702092194,
   "end_elevation_m": 499.8731266573568,
   "start_xy": [
    651249.0225165369,
    4701999.110880051
   ],
   "end_xy": [
    651272.4137870729,
    4701990.309107488
   ]
  },
  "min_50m": {
   "gradient_pct": 0.37801893949392706,
   "start_distance_m": 1410.0,
   "end_distance_m": 1460.0,
   "midpoint_distance_m": 1435.0,
   "start_elevation_m": 499.8034092316539,
   "end_elevation_m": 499.9924187014009,
   "start_xy": [
    651234.4511592772,
    4702005.712596078
   ],
   "end_xy": [
    651281.1168870312,
    4701988.080017824
   ]
  },
  "min_100m": {
   "gradient_pct": 1.8546002889026454,
   "start_distance_m": 1379.0,
   "end_distance_m": 1479.0,
   "midpoint_distance_m": 1429.0,
   "start_elevation_m": 498.81092114253255,
   "end_elevation_m": 500.6655214314352,
   "start_xy": [
    651208.0704261251,
    4702021.8804792985
   ],
   "end_xy": [
    651300.0525303306,
    4701987.638547935
   ]
  }
 },
 "diagnostic_window_maxima": {
  "max_2m": {
   "gradient_pct": 16.55920914485023,
   "start_distance_m": 1066.0,
   "end_distance_m": 1068.0,
   "midpoint_distance_m": 1067.0,
   "start_elevation_m": 472.1717036109368,
   "end_elevation_m": 472.5028877938338,
   "start_xy": [
    651000.3137191605,
    4702254.978893286
   ],
   "end_xy": [
    651001.6245349429,
    4702253.46834306
   ]
  },
  "max_3m": {
   "gradient_pct": 16.313676160920448,
   "start_distance_m": 1065.0,
   "end_distance_m": 1068.0,
   "midpoint_distance_m": 1066.5,
   "start_elevation_m": 472.0134775090062,
   "end_elevation_m": 472.5028877938338,
   "start_xy": [
    650999.6583112692,
    4702255.734168399
   ],
   "end_xy": [
    651001.6245349429,
    4702253.46834306
   ]
  }
 },
 "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": [
   "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_x64y471_MA_Western_B24.tif",
   "data/cache/usa/ma/USGS_1M_18_x65y471_MA_Western_B24.tif"
  ],
  "calculated_at": "2026-08-24T21:53:01+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-1-260824",
  "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_Western_B24 (collected 2023-24)",
  "elevation_tile_ids": [
   "x64y471",
   "x65y471"
  ],
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 12.6% over 200 m (Terrain 50), gain 98.5 m over 1172 m way. EXTENDED by graph walk: +3 segment(s) at base, +3 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 1 overlapping proposal(s): grange-hall-road-2 ADOPTED (NE wave 1, 2026-08-25): big-gain. 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": "Dalton",
  "county": "Massachusetts"
 }
}