{
  "title": "Bay Layers source snapshot",
  "bounds": [
    -122.65,
    37.67,
    -122.27,
    37.95
  ],
  "grid": 513,
  "height_min_m": -113.03356170654297,
  "height_max_m": 783.7405395507812,
  "raw_building_count": 20000,
  "rendered_building_count": 16575,
  "retrieved": "2026-10-17",
  "sources": [
    {
      "id": "noaa",
      "title": "NOAA NCEI topographic/bathymetric DEM mosaic",
      "url": "https://gis.ngdc.noaa.gov/arcgis/rest/services/DEM_mosaics/DEM_all/ImageServer",
      "kind": "observed_derived",
      "notes": "F32 grid resampled to 513\u00d7513. Mosaic combines historical surveys and vertical datums; not current marine navigation or a tidal model. Land and seabed exaggeration are visual."
    },
    {
      "id": "sf-buildings",
      "title": "City and County of San Francisco building footprints, via public ArcGIS mirror",
      "url": "https://data.sf.gov/Geographic-Locations-and-Boundaries/Building-Footprints/ynuv-fyni",
      "mirror": "https://services5.arcgis.com/wXYNaciObHUosEnt/ArcGIS/rest/services/Rooftop_Solar_Power_Potential_San_Francisco_WFL1/FeatureServer/9",
      "kind": "observed_derived",
      "license": "Open Data Commons PDDL (official source)",
      "notes": "20,000-source-feature bounded sample. Simplified footprints and median height; historical city records, not current full Bay Area coverage. Source identifiers retained."
    },
    {
      "id": "motion",
      "title": "Illustrative processes and animated agents",
      "kind": "illustrative",
      "notes": "Wind, currents, solar cycle, wildlife, vessels, cars, flight paths, utility lines and vegetation sketches are designed illustrations, not observed live feeds or a calibrated simulation. Bridge and landmark meshes are stylized, geographically positioned illustrations."
    },
    {
      "id": "sf-streets",
      "title": "SF Public Works street centerlines (2022 mirror snapshot)",
      "url": "https://data.sf.gov/d/3psu-pn9h",
      "mirror": "https://services3.arcgis.com/O2D69KF7KJAcdYlc/arcgis/rest/services/Transit_Stops/FeatureServer/9",
      "kind": "observed_derived",
      "notes": "Partial sampled centerline network; public mirror, historical snapshot. Not current road traffic."
    },
    {
      "id": "sf-trees",
      "title": "SF municipal street-tree inventory (Esri sample mirror, last edited 2018)",
      "url": "https://services.arcgis.com/V6ZHFr6zdgNZuVG0/arcgis/rest/services/Street_Trees/FeatureServer/0",
      "kind": "observed_derived",
      "notes": "8000-point historical sample with mapped locations. Not all trees, not a current inventory, crown sizes stylized."
    },
    {
      "id": "bart",
      "title": "BART Transbay Tube \u2014 contextual reference for illustrative crossing",
      "url": "https://www.bart.gov/news/articles/2024/news20240916",
      "kind": "illustrative_with_geographic_reference",
      "notes": "Approximate route anchored near Embarcadero and West Oakland. Two bores and trains are schematic; vertical placement emphasizes below-water infrastructure and is not a surveyed engineering depth. No real-time train location or timetable. Three sailboats, animated cars and an occasional whale are illustrative."
    },
    {
      "id": "nhdplus",
      "title": "EPA WATERS NHDPlus V2 stream centerlines",
      "url": "https://watersgeo.epa.gov/arcgis/rest/services/NHDPlus/NHDPlus/MapServer/2",
      "kind": "mapped_historical",
      "notes": "Medium-resolution mapped streams, including intermittent channels. Smaller streams retained in this Bay Area crop; adapted from Anselm\u2019s Water Atlas. Not live water extent or discharge. Query URL and feature identifiers retained in hydrography.geojson."
    },
    {
      "id": "marin-vegetation",
      "title": "Marin County Fine Scale Vegetation Map, state agency mirror",
      "url": "https://services2.arcgis.com/Uq9r85Potqm3MfRV/ArcGIS/rest/services/biosds2960_fpu/FeatureServer/0",
      "kind": "mapped_historical",
      "notes": "2018 landscape classification, 2019 LiDAR stand heights. Golden Gate National Parks Conservancy / Tukman Geospatial and project partners. Generalized polygons rasterized to 512-cell grid, grouped forest, scrub and herbaceous cover. Dots are display samples, not individual surveyed trees."
    },
    {
      "id": "osm-regional",
      "title": "OpenStreetMap regional roads and buildings",
      "url": "https://www.openstreetmap.org/copyright",
      "license": "ODbL 1.0",
      "kind": "mapped_snapshot",
      "notes": "Regional footprints spatially sampled outside SF. Height or levels used where present; otherwise an illustrative 6.2 m default. Major roads emphasized. Way IDs and query retained in regional assets and preparation cache."
    }
  ],
  "street_segments": 12000,
  "mapped_street_trees": 8000,
  "regional_building_count": 6592,
  "regional_road_features": 27540,
  "vegetation_display_patches": 33471
}