{
  "method": "USGS EPQS v1 few-point transect across 13-ac road-depth strip polygon (strip_13ac_from_road.json)",
  "crs": "EPSG:4326",
  "units": "feet",
  "queried_pt": "2026-09-22 PT",
  "strip_bbox": {
    "min_lon": -121.21034202206346,
    "max_lon": -121.20801566625,
    "min_lat": 38.09154442772227,
    "max_lat": 38.0941281250065
  },
  "points": {
    "strip_N_mid": {
      "lon": -121.20917884415672,
      "lat": 38.0940781250065,
      "elev_ft": 60.497483615709434,
      "error": null
    },
    "strip_N_third": {
      "lon": -121.20917884415672,
      "lat": 38.09326689257842,
      "elev_ft": 60.878878260460006,
      "error": null
    },
    "strip_centroid_approx": {
      "lon": -121.20917884415672,
      "lat": 38.09283627636438,
      "elev_ft": 60.93660559498444,
      "error": null
    },
    "strip_S_third": {
      "lon": -121.20917884415672,
      "lat": 38.09240566015035,
      "elev_ft": 61.03965749460755,
      "error": null
    },
    "strip_S_mid": {
      "lon": -121.20917884415672,
      "lat": 38.09159442772227,
      "elev_ft": 61.27204365033788,
      "error": null
    },
    "strip_NW": {
      "lon": -121.21019202206345,
      "lat": 38.094028125006496,
      "elev_ft": 60.188077614994796,
      "error": null
    },
    "strip_NE": {
      "lon": -121.20816566625001,
      "lat": 38.094028125006496,
      "elev_ft": 61.967568866164235,
      "error": null
    },
    "strip_SW": {
      "lon": -121.21019202206345,
      "lat": 38.09164442772227,
      "elev_ft": 60.611067231548844,
      "error": null
    },
    "strip_SE": {
      "lon": -121.20816566625001,
      "lat": 38.09164442772227,
      "elev_ft": 61.7007402946336,
      "error": null
    },
    "parcel_centroid_prior": {
      "lon": -121.209028,
      "lat": 38.092006,
      "elev_ft": 61.31210548232852,
      "error": null
    }
  },
  "min_ft": 60.188077614994796,
  "max_ft": 61.967568866164235,
  "range_ft": 1.7794912511694392,
  "n_points": 10,
  "ns_span_ft_approx": 940.4658114596884,
  "ew_span_ft_approx": 670.4557454367631,
  "label": "RESEARCHED",
  "note": "Public DEM point samples \u2014 NOT survey grade; radiation frost / cold-air drainage still UNKNOWN without logger/field walk. Flat \u2260 frost-free.",
  "ns_gradient_ft_per_1000ft": 1.892,
  "epqs_endpoint": "https://epqs.nationalmap.gov/v1/json",
  "epqs_params_note": "wkid=4326 units=Feet; no layer override \u2014 service-selected DEM",
  "epqs_response_fields_observed": {
    "rasterId": 113219,
    "resolution_m": 1,
    "interpretation": "USGS EPQS v1 returned resolution=1 (meters) and rasterId=113219 for strip points and the prior centroid sample in elev.json. Per EPQS docs, resolution is the source DEM cell size in meters \u2014 this is the 1-meter 3DEP product, NOT the 1/3-arc-second (~10 m) product."
  },
  "magnitude_caveat_vs_claude_adb34b21": "WITHDRAWN cell-size comparison (Claude fd423237). Restated per Claude 7c21ab90: headline vs 95% NVA \u22482.76\u00d7 (secondary \u22485.4\u00d7 RMSEz) using strip relief 0.54 m against ~0.1 m QL1/QL2 RMSEz spec ceiling. U6 remains NARROWED not CLOSED. Project-specific NVA not yet source-inspected.",
  "disclosure_updated_pt": "2026-09-22 ~10:30 PM PT",
  "magnitude_yardstick": {
    "correct_comparator": "3DEP non-vegetated vertical accuracy (RMSEz / NVA), NOT horizontal cell size (GSD)",
    "observed_relief_ft": 1.7794912511694392,
    "observed_relief_m": 0.5423889333564451,
    "arithmetic_note": "Strip range to 2 dp: 0.54 m (raw 0.5424 m from 1.779 ft). Multiples follow that figure: 5.4\u00d7 RMSEz and 2.76\u00d7 95% NVA (avoid 5.4 vs 5.5 ambiguity from rounding relief to 0.55 before dividing). Prior cell-size comparison remains wrong.",
    "order_of_magnitude_rmsez_m_ql1_ql2": 0.1,
    "source_for_rmsez_order": "USGS 3DEP published non-vegetated vertical accuracy for QL1/QL2 lidar-derived DEMs is on the order of ~0.1 m RMSEz (Claude fd423237 named this yardstick; project-specific NVA/collection year NOT yet pulled from 3DEP metadata for rasterId 113219)",
    "multiples_of_rmsez": 5.4,
    "conclusion": "Headline multiple uses 95% NVA (\u22482.76\u00d7). Secondary: \u22485.4\u00d7 RMSEz. Both support 'relief resolvable above DEM noise.' Conclusion from 0b793df3 survives; cell-size reasoning withdrawn. Claude 7c21ab90 method-narrowing applied.",
    "still_holds": [
      "RESEARCHED model points \u2014 not survey grade",
      "U6 frost pocket = NARROWED, not CLOSED",
      "resolution:1 establishes 1 m product identity only \u2014 not QL, collection year, or vertical datum",
      "If transect is leaned on harder later: cite 3DEP project name + collection date + published NVA from metadata, not rasterId alone"
    ],
    "observed_relief_m_2dp": 0.54,
    "approx_95pct_nva_m_from_rmsez": 0.196,
    "multiples_of_95pct_nva": 2.76,
    "headline_comparator": "95pct_NVA",
    "headline_multiple": 2.76,
    "headline_statement": "Against QL1/QL2 ~0.1 m RMSEz spec ceiling (\u22480.196 m at 95% NVA), observed strip relief 0.54 m is \u22482.76\u00d7 the 95% NVA (\u22485.4\u00d7 RMSEz). Relief remains resolvable above DEM vertical noise; cell-size reasoning stays withdrawn.",
    "spec_ceiling_caveat": "~0.1 m is the 3DEP QL1/QL2 RMSEz spec ceiling, not this project's measured NVA. Project-level NVA for covering collect (rasterId 113219) still UNKNOWN; until pulled, relief claim is spec-level not project-level."
  },
  "magnitude_restated_vs_claude_fd423237_pt": "2026-09-22T22:51:35-07:00",
  "magnitude_restated_vs_claude_7c21ab90_pt": "2026-09-23T07:43:18-07:00",
  "claude_7c21ab90_applied": {
    "restatement_accepted": true,
    "docs_hash_verify_pass": true,
    "arithmetic_nit": "use 2 dp relief; avoid 5.4 vs 5.5 ambiguity from rounded 0.55 input",
    "method_narrowing": "headline multiple = vs 95% NVA; disclose RMSEz multiple as secondary; note spec ceiling"
  }
}