{
  "name": "西域环游记 — 真实高程网格",
  "bounds": [
    72.0,
    31.0,
    116.0,
    52.0
  ],
  "boundsOrder": "west,south,east,north",
  "width": 640,
  "height": 400,
  "rowOrder": "north-to-south",
  "columnOrder": "west-to-east",
  "registration": "grid-node; inclusive bounds; first pixel=(west,north), last pixel=(east,south)",
  "horizontalCRS": "EPSG:4326",
  "horizontalDatum": "WGS84",
  "encoding": "int16-little-endian",
  "units": "meters",
  "offset": 0,
  "file": "heightmap.bin",
  "pngFile": "heightmap-offset32768.png",
  "pngEncoding": "uint16 grayscale elevationMeters+32768; do not decode as 8-bit grayscale",
  "bytes": 512000,
  "sha256": "ac25f2e4e5306a129c395647a30be5769316b9052f74154a5c7e10374cb81971",
  "source": "Mapzen Terrain Tiles (Terrarium) via AWS Open Data; SRTM with GMTED2010 and ETOPO1 fallbacks",
  "sourceUrl": "https://registry.opendata.aws/terrain-tiles/",
  "sourceDocumentation": "https://github.com/tilezen/joerd/blob/master/docs/data-sources.md",
  "formatDocumentation": "https://github.com/tilezen/joerd/blob/master/docs/formats.md",
  "attributionUrl": "https://github.com/tilezen/joerd/blob/master/docs/attribution.md",
  "tileEndpoint": "https://s3.amazonaws.com/elevation-tiles-prod/terrarium/{z}/{x}/{y}.png",
  "tileZoom": 7,
  "tileCount": 187,
  "tilePixelSize": 256,
  "sourceDatasetsInHeaders": [
    "etopo1",
    "gmted",
    "srtm"
  ],
  "attribution": "Terrain Tiles: Mapzen / Tilezen; SRTM and GMTED2010 data courtesy of the U.S. Geological Survey. ETOPO1: DOC/NOAA/NESDIS/NCEI, U.S. Department of Commerce.",
  "license": "Underlying SRTM, GMTED2010 and ETOPO1 are public-domain US Government datasets. Required/requested provider credits retained; see attributionUrl.",
  "verticalDatum": "EGM96 geoid for primary SRTM data; tiles composite SRTM and GMTED2010, and no additional vertical transformation is applied.",
  "datumSource": "https://www.usgs.gov/centers/eros/science/usgs-eros-archive-digital-elevation-shuttle-radar-topography-mission-srtm",
  "accessed": "2026-10-17",
  "resampling": "Terrarium RGB decoded to meters, bilinear resampling in EPSG:3857 onto an equally spaced EPSG:4326 vertex grid; rounded to nearest meter.",
  "resolutionApproxKm": {
    "eastWestAtMidLatitude": 5.734,
    "northSouth": 5.852
  },
  "sourceTilePixelApproxKmAtMidLatitude": 0.916,
  "nativeSourceResolutionNote": "Underlying SRTM is nominally 30m (90m nominal quality per Tilezen); zoom-7 tile pixels are approx 0.9km and this display grid approx 5.7km. Display-grid spacing is not original DEM resolution.",
  "minElevation": -157,
  "maxElevation": 6983,
  "p01Elevation": 54,
  "p99Elevation": 5458,
  "verticalExaggeration": "Applied by renderer, not baked into this DEM. 1x means geometric scale; any artistic exaggeration must be labeled.",
  "limitations": [
    "Regional relief presentation, not a navigation or survey product.",
    "Coarse mesh does not resolve roads, narrow valleys, or summit elevations; mountain peaks can be underestimated.",
    "No GPS route is included: itinerary route links remain a geographic schematic.",
    "WGS84 coordinates are used consistently for DEM and route. No GCJ-02/BD-09 conversion."
  ]
}