{
  "id": "fairyland-point",
  "name": "Fairyland Point sector",
  "group": "Beyond the main bowl",
  "center": [
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  "width_m": 768,
  "priority": 1,
  "source_ids": [
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  "question": "How does a headwater hollow divide into smaller gullies?",
  "interaction": "section",
  "theme": "Another amphitheater",
  "view_yaw": 1.25,
  "view_pitch": 0.74,
  "schema": 1,
  "kind": "landscape-study",
  "checked_at": "2026-10-02",
  "surface_method": "upper-envelope",
  "geometry_status": "Derived from measured airborne returns; upper-envelope terrain study, not a closed rock scan",
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    "ept_horizontal": "WGS84 Pseudo-Mercator (EPSG:3857)",
    "export_horizontal": "WGS84 / UTM 12N (EPSG:32612)",
    "vertical": "NAVD88, Geoid12B; source heights retained",
    "units": "metres",
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    "vertical_exaggeration": 1,
    "transform_note": "EPT projection transformed with pyproj; no claim of survey-grade datum alignment. Centimetre export quantization is not source accuracy."
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    "returns_in_crop": 18386528,
    "density_returns_per_m2": 31.173,
    "ground_returns": 5829053,
    "retained_returns": 13108120,
    "vegetation_candidate_returns": 5278408,
    "excluded_noise_or_other": 5722,
    "directly_observed_node_fraction": 0.9973553116058502,
    "interpolated_node_fraction": 0.0026446883941497667,
    "unsupported_node_fraction": 0.0,
    "isolated_high_cells_repaired": 179,
    "maximum_nearest_fill_m": 3.0,
    "cell_m": 1.5,
    "source_heights_m": [
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    "surface_heights_m": [
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    "intensity_display_percentiles": [
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      11632.0
    ],
    "vertical_surfaces": "An upper envelope can join returns across a steep face; it cannot recover undercuts, windows, or unseen interiors.",
    "surface_method": "upper-envelope"
  },
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      "id": "small",
      "vertices": 16641,
      "triangles": 32768,
      "grid_nodes": 129,
      "spacing_m": 6.0,
      "degenerate_triangles": 0,
      "downward_triangles": 0
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      "vertices": 66049,
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      "spacing_m": 3.0,
      "degenerate_triangles": 0,
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      "id": "detailed",
      "vertices": 263169,
      "triangles": 524288,
      "grid_nodes": 513,
      "spacing_m": 1.5,
      "degenerate_triangles": 0,
      "downward_triangles": 0
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  "returns": {
    "file": "returns.glb.gz",
    "bytes": 1220744,
    "uncompressed_bytes": 2881228,
    "sha256": "b945fa9c024e9fe67cd77ab62338600c5b34d7781c7a59543deaa18b48ec0b44",
    "count": 120000,
    "sampling": "fixed seed 20261002, uniform without replacement from valid crop returns"
  },
  "profiles": "profiles.json.gz",
  "camera": {
    "yaw": 1.25,
    "pitch": 0.74,
    "distance_m": 1536,
    "target": [
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  },
  "bounds_local": [
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      -384.0
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    [
      384.0,
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  "source_dataset": {
    "id": "USGS_LPC_UT_Southern_QL1_2018_LAS_2019",
    "acquired": "2018-04-27 / 2018-07-29 project interval",
    "published": "2019-06-03",
    "url": "https://registry.opendata.aws/usgs-lidar/",
    "license": "US Government Public Domain",
    "credit": "Map services and data available from U.S. Geological Survey, National Geospatial Program."
  },
  "processing": {
    "mesh": "Vegetation heuristic applied to an upper envelope. Highest retained return per nearest grid node; nearest interpolation up to 3 m; isolated spikes exceeding all 8 neighbors by 6 m lowered to neighbor maximum. No morphological closing.",
    "vegetation": "Source classes 3/4/5 plus low-intensity multiple echoes and low-intensity raised returns over nearby gentle classified ground are excluded. This is an imperfect heuristic, not a species/rock classifier.",
    "lighting": "Normals and static 12-direction terrain occlusion are derived; material color, studio lighting and display category colors are illustrative.",
    "detail": "Three nested node grids; no-data cells omitted at every LOD; low LOD can omit extra edge triangles to preserve holes."
  },
  "limitations": [
    "Hidden rock surfaces, undercuts and windows are not reconstructed.",
    "A vertical face is an interpolated connection between top-surface samples, not a wall scan.",
    "Vegetation filtering can leave crowns or remove dark rock; inspect the return view.",
    "NAIP is overhead imagery from a different year; it cannot supply photographic detail on vertical faces.",
    "The cut boundary is an editorial crop; there is no modeled geology beneath it.",
    "No route, current condition, erosion rate or collapse forecast is inferred."
  ],
  "posters": {
    "large": "poster.webp",
    "small": "poster-small.webp"
  },
  "quality_status": "accepted_educational_landscape",
  "quality_record": "quality.json",
  "textures": [
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      "file": "aerial.webp",
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      "height": 1280,
      "bytes": 530888,
      "sha256": "56b055dd61ad507f10d561ee530824385aa50cfd532e145b043059c130a49cc9",
      "source": "imagery.json",
      "license": "US Government Public Domain, USDA NAIP"
    },
    {
      "file": "aerial-small.webp",
      "width": 512,
      "height": 512,
      "bytes": 110250,
      "sha256": "4736d4867e305693516bdde268b6a7c44d274725f1baafe003388b79a96d174d",
      "source": "imagery.json",
      "license": "US Government Public Domain, USDA NAIP"
    }
  ]
}