{
  "benchmark": "terrain-representation-fidelity/v1",
  "input_kind": "real public USGS DEM export",
  "measures": "deviation of an interpolated lower-resolution representation from the downloaded raster",
  "does_not_measure": [
    "absolute terrain accuracy",
    "independent source registration",
    "localization accuracy",
    "browser rendering performance"
  ],
  "source_sha256": "b7c5c094915a628b74c1a0d72fcd612c6458b45f233256e849691c636ec61fcb",
  "input_grid": [
    512,
    512
  ],
  "finite_fraction": 1.0,
  "height_min_m": 166.681640625,
  "height_max_m": 1364.614990234375,
  "served_extent": {
    "xmin": 287085.8547033373,
    "ymin": 3812110.209772141,
    "xmax": 294994.6970874284,
    "ymax": 3820019.0521562323,
    "spatialReference": {
      "wkid": 26911,
      "latestWkid": 26911
    }
  },
  "export_pixel_spacing_m": 15.446957781427955,
  "method": "endpoint-preserving bilinear resampling of pixel centers; downsample to each grid then reconstruct at all 512x512 source centers",
  "timing_qualification": "one diagnostic CPU run; not a performance benchmark or hardware comparison",
  "python": "3.12.14",
  "numpy": "2.3.5",
  "results": [
    {
      "grid": [
        256,
        256
      ],
      "height_samples": 65536,
      "sample_reduction_fraction": 0.75,
      "reconstruction_rmse_m": 1.6255876063575385,
      "reconstruction_abs_p95_m": 3.6649049056857956,
      "reconstruction_abs_max_m": 16.237690956609242,
      "height_npz_bytes": 224006,
      "single_run_cpu_ms": 15.286242000001948
    },
    {
      "grid": [
        128,
        128
      ],
      "height_samples": 16384,
      "sample_reduction_fraction": 0.9375,
      "reconstruction_rmse_m": 3.936519682808641,
      "reconstruction_abs_p95_m": 8.923770403557487,
      "reconstruction_abs_max_m": 33.67253093117665,
      "height_npz_bytes": 56574,
      "single_run_cpu_ms": 10.624367001582868
    },
    {
      "grid": [
        64,
        64
      ],
      "height_samples": 4096,
      "sample_reduction_fraction": 0.984375,
      "reconstruction_rmse_m": 8.77558487532058,
      "reconstruction_abs_p95_m": 19.85799984694825,
      "reconstruction_abs_max_m": 54.10105157538277,
      "height_npz_bytes": 14627,
      "single_run_cpu_ms": 7.330732998525491
    },
    {
      "grid": [
        32,
        32
      ],
      "height_samples": 1024,
      "sample_reduction_fraction": 0.99609375,
      "reconstruction_rmse_m": 18.09044771771558,
      "reconstruction_abs_p95_m": 40.94267346450804,
      "reconstruction_abs_max_m": 105.44457828882378,
      "height_npz_bytes": 3864,
      "single_run_cpu_ms": 6.583667996892473
    }
  ],
  "limitations": [
    "The original raster is a service-resampled reference, not independent ground truth.",
    "No acquisition freshness, absolute vertical accuracy, or geodetic-integrity claim is established.",
    "Export output extent is authoritative and differs from requested WGS84 bbox because the service adjusted aspect ratio.",
    "Sampling error can suppress narrow terrain features; these grids are presentation artifacts."
  ]
}