{
  "exampleLocation": "Unnamed aggregate quarry in central California",
  "locationPolicy": "Marketing copy omits the quarry and operator name. Coordinates remain public for reproducibility; this does not anonymize the site.",
  "operatorRelationship": "Public data example only. No customer relationship, site access, endorsement, or GPSCS capture is claimed.",
  "retrieved": "2026-09-18",
  "elevation": {
    "provider": "USGS 3D Elevation Program (3DEP)",
    "project": "CA_AZ_FEMA_R9_Lidar_2017_D18",
    "type": "LiDAR-derived bare-earth DEM, not raw LiDAR points",
    "sourceNominalResolutionM": 1,
    "browserSampleSpacingApproxM": 4,
    "catalogRasterIds": [
      33392,
      41700
    ],
    "catalogAcquisitionDateField": "2019-02-24 (catalog value; not independently verified as flight date)",
    "request": "https://elevation.nationalmap.gov/arcgis/rest/services/3DEPElevation/ImageServer/exportImage?f=json&bbox=-13539940.729046917%2C4424330.166861097%2C-13537189.572527362%2C4426581.113104369&bboxSR=3857&size=551%2C451&format=tiff&pixelType=F32&imageSR=3857&renderingRule=%7B%22rasterFunction%22%3A+%22None%22%7D&mosaicRule=%7B%22mosaicMethod%22%3A+%22esriMosaicLockRaster%22%2C+%22lockRasterIds%22%3A+%5B33392%2C+41700%5D%7D&interpolation=RSP_BilinearInterpolation",
    "exportExtent": {
      "xmin": -13539940.729046917,
      "ymin": 4424329.712949776,
      "xmax": -13537189.572527362,
      "ymax": 4426581.567015691,
      "spatialReference": {
        "wkid": 102100,
        "latestWkid": 3857
      }
    },
    "grid": [
      551,
      451
    ],
    "encoding": "Little-endian uint16, offset + value * 0.01 m; encoding precision is not measurement accuracy.",
    "service": "https://elevation.nationalmap.gov/arcgis/rest/services/3DEPElevation/ImageServer",
    "use": "U.S. Government work, public domain; no licensed third-party elevation product.",
    "originalTiles": [
      "https://prd-tnm.s3.amazonaws.com/StagedProducts/Elevation/1m/Projects/CA_AZ_FEMA_R9_Lidar_2017_D18/TIFF/USGS_1M_10_x61y409_CA_AZ_FEMA_R9_Lidar_2017_D18.tif",
      "https://prd-tnm.s3.amazonaws.com/StagedProducts/Elevation/1m/Projects/CA_AZ_FEMA_R9_Lidar_2017_D18/TIFF/USGS_1M_10_x62y409_CA_AZ_FEMA_R9_Lidar_2017_D18.tif"
    ]
  },
  "imagery": {
    "provider": "USDA NAIP / USGS The National Map",
    "service": "https://imagery.nationalmap.gov/arcgis/rest/services/USGSNAIPImagery/ImageServer",
    "request": "https://imagery.nationalmap.gov/arcgis/rest/services/USGSNAIPImagery/ImageServer/exportImage?f=image&bbox=-13539940.729046917%2C4424329.712949776%2C-13537189.572527362%2C4426581.567015691&bboxSR=3857&imageSR=3857&size=2200%2C1800&format=jpg&compressionQuality=92&bandIds=0%2C1%2C2&mosaicRule=%7B%22mosaicMethod%22%3A+%22esriMosaicLockRaster%22%2C+%22lockRasterIds%22%3A+%5B20308%2C+20313%5D%7D",
    "requestNote": "The recorded request pins catalogRasterIds via mosaicRule, so replaying it returns the recorded capture rather than the current NAIP mosaic; tools/fetch-quarry-sources.py verifies that lock is present instead of adding it. The recorded sha256 below was produced before the lock was written into this URL, from the same bbox and size without the mosaicRule, so a first locked fetch that differs by a server-side re-encode must be reviewed, not waved through.",
    "use": "Public-domain NAIP imagery; no third-party commercial basemap tiles.",
    "dateNote": "Imagery and elevation may represent different acquisition dates. This is an illustrative historical context model, not a current synchronized capture.",
    "acquisitionDate": "2022-05-14",
    "catalogRasterIds": [
      20308,
      20313
    ],
    "sourceNominalResolutionM": 0.6
  },
  "subsurface": {
    "status": "Wholly synthetic teaching/demo scenario",
    "description": "Synthetic ERT-like observations, borehole logs, candidate lithologies, probabilities, and verification priorities. Surface LiDAR supplies no underground measurements.",
    "ranking": "Heuristic uncertainty score, not validated drilling optimization or a geological reserve estimate.",
    "surveyWindow": {"widthM": 720, "contextHeightM": 600, "fullCropU0": 0.42, "fullCropU1": 0.7472727272727273, "fullCropV": 0.53},
    "modelScale": {"horizontal": 3, "depth": 3},
    "depthLimitM": 78,
    "minimumCoverage": 0.22,
    "minimumPeakBernoulliVariance": 0.001,
    "volumeDisplay": {"crossLineWidthM": 160, "maxDisplayedDepthM": 108, "method": "Copy 2D scenario probabilities at matching depth below the local DEM across an illustrative swath", "crossLineGeometryMeasured": false}
  },
  "drainageDisplay": {
    "input": "Bundled public elevation DEM",
    "derivedAsset": "assets/quarry-drainage.js - flow paths and ponding basins computed offline from the same DEM by the GPSCS drainage engine via tools/build-quarry-drainage.py. The page renders these when the file is present; the asset's own meta block records the engine version, method, threshold label and cell size.",
    "browserFallback": "The in-page routing described by the keys below runs only when that asset is missing.",
    "gridColumns": 184,
    "approximateSpacingM": 12,
    "method": "Strict downhill D8 plus contributing-cell accumulation",
    "minimumDisplayedContributingCells": 18,
    "depressionsAndFlats": "Retained; terminate routes",
    "limits": "Historical unconditioned surface; no rainfall, water depth, infrastructure, infiltration or pumping model. Animation speed is illustrative.",
    "methodReferences": ["https://doc.esri.com/en/arcgis-pro/latest/tool-reference/spatial-analyst/how-flow-direction-works.html", "https://doc.esri.com/en/arcgis-pro/latest/tool-reference/spatial-analyst/how-flow-accumulation-works.html"]
  },
  "files": {
    "data/USGS-3DEP-quarry-crop.tif": {"role": "Raw elevation export, downloaded locally; excluded from release and version control", "sha256": "2bff5868851aca2ef667bbca14c2177956667ac64df8ed91c0baabddf442f4c9"},
    "data/quarry-aerial.jpg": {"role": "Raw NAIP image export, downloaded locally; excluded from release and version control", "sha256": "873d39731eff34f72647beed3b9c145f0c1f97cfe77f544c7d7aa79dbe242e16"},
    "assets/quarry-data.js": {"role": "Quantized browser elevation excerpt", "sha256": "61aa2fc92fd26fde75cace67bbbc4e6213f233ec15cd8b308c8e160bfb6298c8"},
    "assets/quarry-texture.js": {"role": "Single downsampled NAIP texture shared by 3D and static fallback", "sha256": "0933db3d5a06d871b4e6f0e05ee596e089adb71fbcc7b542cab0d5c7c1b61a61"},
    "assets/quarry-drainage.js": {
      "role": "Flow paths and ponding basins derived from data/USGS-3DEP-quarry-crop.tif (sha256 2bff5868851aca2ef667bbca14c2177956667ac64df8ed91c0baabddf442f4c9) by the GPSCS drainage engine via tools/build-quarry-drainage.py. No new source data; terrain routing only, no water is measured.",
      "engine": "GPSCS drainage engine",
      "engineVersion": "0.1.0",
      "threshold": "contributing area \u2265 0.81 ha (2 acres, the tool's --threshold-acres default)",
      "cellM": 4.0,
      "contents": "118 flow paths (3136 vertices) and 30 ponding basins (1035 ring vertices), u/v in the full DEM crop",
      "sha256": "f0e2db5c397392dd2689ea2a732beb057709c933aa7fb720858acd2c01133db1",
      "hashNote": "Not checked by tools/build-quarry-assets.py, which verifies only the two payload assets above. Re-record this value with tools/build-quarry-drainage.py, which prints it."
    }
  }
}