{
  "id": "yangtze-estuary",
  "formatVersion": 2,
  "bounds": [
    120.86246,
    31.00655,
    122.33754,
    31.79345
  ],
  "boundsNote": "140 x 87.5 km (16:10) centred on lon 121.6, lat 31.4 in the local equirectangular approximation (sphere R = 6371008.8 m)",
  "projection": "WGS84 lon/lat, quantized linearly; render with x scaled by cos(centre latitude)",
  "accessDate": "2026-10-04",
  "output": {
    "file": "yangtze-estuary-v1.json",
    "bytes": 1055262,
    "gzipBytes": 291589,
    "sha256": "02d075e1fb50449e620aa4309bb6c4e5ec12a05058455e5a05ea5c7b3a077436"
  },
  "sources": [
    {
      "name": "Protomaps basemap, daily planet build (OpenStreetMap data)",
      "url": "https://build.protomaps.com/20261004.pmtiles",
      "build": "20261004.pmtiles",
      "basemapVersion": "4.15.2",
      "license": "Open Data Commons Open Database License (ODbL) 1.0",
      "licenseUrl": "https://opendatacommons.org/licenses/odbl/1-0/",
      "copyrightUrl": "https://www.openstreetmap.org/copyright",
      "attribution": "© OpenStreetMap contributors; basemap tiles by Protomaps (https://protomaps.com)",
      "accessDate": "2026-10-04",
      "vectorZoom": 11,
      "tiles": 54,
      "use": "Roads, rail, waterways, water incl. ocean, parks, woods, glaciers"
    },
    {
      "name": "AWS Terrain Tiles (Tilezen Joerd), Terrarium PNG",
      "url": "https://s3.amazonaws.com/elevation-tiles-prod/terrarium/{z}/{x}/{y}.png",
      "license": "Mixed open sources (USGS 3DEP, SRTM, GMTED2010 public domain; ETOPO1 NOAA; EU-DEM Copernicus; others)",
      "licenseUrl": "https://github.com/tilezen/joerd/blob/master/docs/attribution.md",
      "attribution": "SRTM and GMTED2010 data courtesy of the U.S. Geological Survey",
      "attributionFull": [
        "ArcticDEM terrain data DEM(s) were created from DigitalGlobe, Inc., imagery and funded under National Science Foundation awards 1043681, 1559691, and 1542736;",
        "Australia terrain data © Commonwealth of Australia (Geoscience Australia) 2017;",
        "Austria terrain data © offene Daten Österreichs – Digitales Geländemodell (DGM) Österreich;",
        "Canada terrain data contains information licensed under the Open Government Licence – Canada;",
        "Europe terrain data produced using Copernicus data and information funded by the European Union - EU-DEM layers;",
        "Global ETOPO1 terrain data U.S. National Oceanic and Atmospheric Administration",
        "Mexico terrain data source: INEGI, Continental relief, 2016;",
        "New Zealand terrain data Copyright 2011 Crown copyright (c) Land Information New Zealand and the New Zealand Government (All rights reserved);",
        "Norway terrain data © Kartverket;",
        "United Kingdom terrain data © Environment Agency copyright and/or database right 2015. All rights reserved;",
        "United States 3DEP (formerly NED) and global GMTED2010 and SRTM terrain data courtesy of the U.S. Geological Survey."
      ],
      "attributionNote": "Required attribution list from the Joerd attribution document. The short credit names the sources that cover this view; sea-floor values (ETOPO1) are clamped to 0 m.",
      "accessDate": "2026-10-04",
      "use": "Elevation grid"
    }
  ],
  "processing": {
    "category": "deltas",
    "style": "water-shapes",
    "roadClasses": [],
    "lineClasses": [
      "river",
      "stream",
      "canal"
    ],
    "polygonClasses": [
      "water",
      "wetland"
    ],
    "classMapping": "tools/data/protomaps_classes.json",
    "quant": 65535,
    "referenceOutputWidthPx": 3840,
    "lineSimplifyToleranceM": 5.0,
    "polygonSimplifyToleranceM": 8.0,
    "minLineLengthPx": 2.0,
    "minPolygonAreaPx2": 4.0,
    "maxProtectedAreaFraction": 0.3,
    "elevationClampBelowM": 0,
    "derived": {
      "widthM": 140001,
      "heightM": 87499,
      "pxM": 36.46
    },
    "elevation": {
      "zoom": 10,
      "tiles": 20,
      "sourcePixelM": 130.5,
      "despikedPixels": 7,
      "despikeThresholdM": 100.0,
      "sampling": "bilinear at cell centres",
      "pitsFilled": 0,
      "pitThresholdM": 300.0,
      "columns": 600,
      "rows": 375,
      "rawMin": -90.4,
      "rawMax": 74.2,
      "cellM": [
        233.3,
        233.3
      ]
    },
    "dropped": {
      "river short": 77,
      "canal short": 537
    }
  },
  "featureCounts": {
    "motorway": 0,
    "trunk": 0,
    "primary": 0,
    "secondary": 0,
    "tertiary": 0,
    "residential": 0,
    "service": 0,
    "rail": 0,
    "river": 1649,
    "stream": 0,
    "canal": 8318,
    "water": 1438,
    "park": 0,
    "wood": 0,
    "glacier": 0,
    "wetland": 62
  },
  "pointCount": 72301,
  "largestPolygonsKm2": {
    "water": [
      4849.217,
      97.561,
      42.291,
      7.031,
      6.982
    ],
    "glacier": []
  },
  "label": {
    "name": "Yangtze Estuary",
    "nativeName": "长江口",
    "region": "China",
    "regionCode": "CN",
    "source": "views/catalog.json",
    "nativeLang": "zh-Hans"
  },
  "limitations": [
    "OSM data is a snapshot of the Protomaps build named above.",
    "Geometry comes from zoom-level vector tiles, merged across tiles and simplified for about 3840 px across the view; not for navigation or analysis.",
    "Tunnels and bridges are not distinguished; footways, paths, and tracks are not included.",
    "Elevation is bilinearly resampled from Web Mercator tiles to a coarse lon/lat grid; values below 0 m are clamped to 0 m."
  ],
  "requiredAttribution": "© OpenStreetMap contributors · Protomaps · Elevation: SRTM and GMTED2010 data courtesy of the U.S. Geological Survey"
}