{
  "schema_version": "1.0",
  "asset": "Elevation product selection evidence",
  "version": "2026-10-24",
  "license": "CC-BY-4.0",
  "license_scope": "Original compiled observations and annotations only. Source datasets, software and documentation retain their own terms. No source datasets are redistributed.",
  "generated_utc": "2026-10-25T00:10:17.059140+00:00",
  "observed_date_local": "2026-10-24",
  "timezone": "America/Denver",
  "row_count": 20,
  "comparison_attributes": [
    "surface_representation",
    "geographic_coverage",
    "grid_spacing",
    "horizontal_reference",
    "vertical_reference",
    "vertical_unit",
    "pixel_registration",
    "acquisition_period",
    "source_sensor",
    "void_fill_sources",
    "water_treatment",
    "data_type",
    "file_format",
    "tile_unit",
    "nodata_value",
    "accuracy_metric_basis",
    "quality_layers",
    "release_strategy",
    "access_condition",
    "reuse_condition"
  ],
  "method_summary": "Twenty exact product profiles. These are provider specifications and conditions, not measured local accuracy. Angular spacing is not a fixed ground distance; DSM, DTM and mixed sources are distinguished.",
  "rows": [
    {
      "record_id": "E01",
      "item_name": "USGS 3DEP 1-metre DEM",
      "source_url": "https://www.usgs.gov/3d-elevation-program/about-3dep-products-services",
      "source_version": "Current overview",
      "audit_status": "Primary product documentation inspected; no raster accuracy measurement",
      "surface_representation": "Bare earth",
      "geographic_coverage": "US project coverage; expanding",
      "grid_spacing": "1 metre",
      "horizontal_reference": "NAD83 / UTM; inspect actual tile",
      "vertical_reference": "Usually NAVD88; regional exceptions require tile metadata",
      "vertical_unit": "Metres",
      "pixel_registration": "Not established in inspected sources",
      "acquisition_period": "Not established in inspected sources",
      "source_sensor": "Quality level 2 or better lidar",
      "void_fill_sources": "Not established in inspected sources",
      "water_treatment": "Flattened water surfaces",
      "data_type": "Not established in inspected sources",
      "file_format": "GeoTIFF product; actual tile not inspected",
      "tile_unit": "Not established in inspected sources",
      "nodata_value": "Not established in inspected sources",
      "accuracy_metric_basis": "QL2-or-better lidar source; no per-tile accuracy established",
      "quality_layers": "Not established in inspected sources",
      "release_strategy": "Project-based releases",
      "access_condition": "Free public products",
      "reuse_condition": "3DEP no use restrictions; source media rights separate",
      "publisher": "USGS",
      "source_ids": [
        "S006",
        "S051",
        "S058"
      ],
      "sources": [
        {
          "id": "S006",
          "url": "https://www.usgs.gov/3d-elevation-program/about-3dep-products-services",
          "observed_utc": "2026-10-25T00:04:17.874674+00:00",
          "status": "opened",
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          "observation_sha256": null
        },
        {
          "id": "S051",
          "url": "https://www.usgs.gov/faqs/what-projection-horizontal-datum-vertical-datum-and-resolution-a-usgs-digital-elevation-model",
          "observed_utc": "2026-10-25T00:04:23.874849+00:00",
          "status": "opened",
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          "observation_sha256": null
        },
        {
          "id": "S058",
          "url": "https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits",
          "observed_utc": "2026-10-25T00:04:24.630854+00:00",
          "status": "opened",
          "source_body_sha256": "3215bb945b171036dddcaeef80ce2b5869bcf24f5dcaf41e773671493e5c23bc",
          "observation_sha256": null
        }
      ],
      "checked_at_utc": "2026-10-25T00:04:23.874849+00:00",
      "licence": "US public domain (USGS-produced)",
      "licence_source_ids": [
        "S058",
        "S006"
      ],
      "licence_checked_at_utc": "2026-10-25T00:04:24.630854+00:00",
      "licence_quote_ids": []
    },
    {
      "record_id": "E02",
      "item_name": "Copernicus GLO-30 DGED",
      "source_url": "https://dataspace.copernicus.eu/explore-data/data-collections/copernicus-contributing-missions/collections-description/COP-DEM",
      "source_version": "2024_1",
      "audit_status": "Primary product documentation inspected; no raster accuracy measurement",
      "surface_representation": "DSM including buildings and vegetation",
      "geographic_coverage": "Global",
      "grid_spacing": "1 arc-second; nominal 30 metres",
      "horizontal_reference": "WGS84, EPSG:4326",
      "vertical_reference": "EGM2008, EPSG:3855",
      "vertical_unit": "Metres",
      "pixel_registration": "PixelIsPoint",
      "acquisition_period": "Primarily 2011–2015; fillers vary",
      "source_sensor": "TanDEM-X radar with supplementary sources",
      "void_fill_sources": "Multiple older DEMs",
      "water_treatment": "Water flattened; river consistency edits",
      "data_type": "32-bit float",
      "file_format": "GeoTIFF DGED",
      "tile_unit": "1° × 1°",
      "nodata_value": "Not established in inspected sources",
      "accuracy_metric_basis": "Product specification: absolute vertical <4 m LE90; not local validation",
      "quality_layers": "Editing, filling, height-error and water masks",
      "release_strategy": "Versioned releases; 2024_1 inspected",
      "access_condition": "Public licence; service/account conditions differ",
      "reuse_condition": "Custom ESA/Airbus attribution and derivative notices",
      "publisher": "ESA / Airbus",
      "source_ids": [
        "S011",
        "S036"
      ],
      "sources": [
        {
          "id": "S011",
          "url": "https://dataspace.copernicus.eu/explore-data/data-collections/copernicus-contributing-missions/collections-description/COP-DEM",
          "observed_utc": "2026-10-25T00:04:18.448334+00:00",
          "status": "opened",
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          "observation_sha256": null
        },
        {
          "id": "S036",
          "url": "https://dataspace.copernicus.eu/sites/default/files/media/files/2025-06/copernicus_contributing_mission_data_access_v2_cop_dem_licenses.pdf",
          "observed_utc": "2026-10-25T00:04:21.110091+00:00",
          "status": "opened",
          "source_body_sha256": "bb4a01dcd7f61acefa81c9ccd76af975e12096158169acf0d7b5c44c26c8701f",
          "observation_sha256": null
        }
      ],
      "checked_at_utc": "2026-10-25T00:04:21.110091+00:00",
      "licence": "Copernicus DEM ESA–User Licence (instance-specific)",
      "licence_source_ids": [
        "S036"
      ],
      "licence_checked_at_utc": "2026-10-25T00:04:21.110091+00:00",
      "licence_quote_ids": []
    },
    {
      "record_id": "E03",
      "item_name": "ALOS AW3D30",
      "source_url": "https://www.eorc.jaxa.jp/ALOS/en/dataset/aw3d30/aw3d30_e.htm",
      "source_version": "Mixed current 4.1/3.1/4.0",
      "audit_status": "Primary product documentation inspected; no raster accuracy measurement",
      "surface_representation": "DSM",
      "geographic_coverage": "Global with regional version differences",
      "grid_spacing": "Nominal 1 arc-second; longitude angular spacing increases at high latitudes",
      "horizontal_reference": "ITRF97 with GRS80 reference",
      "vertical_reference": "EGM96 orthometric",
      "vertical_unit": "Metres",
      "pixel_registration": "Area average rounded to integer",
      "acquisition_period": "PRISM 2006–2011; supplementary fills vary",
      "source_sensor": "ALOS PRISM optical stereo",
      "void_fill_sources": "Multiple supplementary DEMs, version-dependent",
      "water_treatment": "Sea height zero",
      "data_type": "Signed 16-bit integer",
      "file_format": "GeoTIFF",
      "tile_unit": "1° × 1°",
      "nodata_value": "−9999",
      "accuracy_metric_basis": "Quality fields supplied; no uniform measured local accuracy established",
      "quality_layers": "MSK, STK, QAI and supporting metadata",
      "release_strategy": "4.1 except stated Japan/Antarctic regions",
      "access_condition": "Public distribution under research-data terms",
      "reuse_condition": "JAXA credit; advance notification for commercial research-data use",
      "publisher": "JAXA",
      "source_ids": [
        "S028",
        "S037",
        "S038"
      ],
      "sources": [
        {
          "id": "S028",
          "url": "https://www.eorc.jaxa.jp/ALOS/en/dataset/aw3d30/aw3d30_e.htm",
          "observed_utc": "2026-10-25T00:04:20.042252+00:00",
          "status": "opened",
          "source_body_sha256": "9aff47e836340c40ae010e7295de30d20a8cc6c7f47f5cf385c57b6df2d1a312",
          "observation_sha256": null
        },
        {
          "id": "S037",
          "url": "https://www.eorc.jaxa.jp/ALOS/en/dataset/aw3d30/data/aw3d30v4.1_product_e_1.0.pdf",
          "observed_utc": "2026-10-25T00:04:21.228063+00:00",
          "status": "opened",
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          "observation_sha256": null
        },
        {
          "id": "S038",
          "url": "https://earth.jaxa.jp/en/data/policy/",
          "observed_utc": "2026-10-25T00:04:21.499094+00:00",
          "status": "opened",
          "source_body_sha256": "5a3da04f065c17f42afddbc388996988c838c892e7d8f35832db18b2e37ac495",
          "observation_sha256": null
        }
      ],
      "checked_at_utc": "2026-10-25T00:04:21.499094+00:00",
      "licence": "JAXA Terms of Use of Research Data",
      "licence_source_ids": [
        "S038"
      ],
      "licence_checked_at_utc": "2026-10-25T00:04:21.499094+00:00",
      "licence_quote_ids": [
        "TQ-S038-5c101db7"
      ]
    },
    {
      "record_id": "E04",
      "item_name": "ArcticDEM 2-metre strips",
      "source_url": "https://www.pgc.umn.edu/data/arcticdem/",
      "source_version": "Current strips documentation",
      "audit_status": "Primary product documentation inspected; no raster accuracy measurement",
      "surface_representation": "DSM",
      "geographic_coverage": "Arctic; public Alaska dates restricted",
      "grid_spacing": "2 metres",
      "horizontal_reference": "Not established in inspected sources",
      "vertical_reference": "WGS84 ellipsoid",
      "vertical_unit": "Metres",
      "pixel_registration": "Not established in inspected sources",
      "acquisition_period": "Optical imagery 2007–2024; strip-specific",
      "source_sensor": "Commercial optical stereo",
      "void_fill_sources": "Not established in inspected sources",
      "water_treatment": "Not established in inspected sources",
      "data_type": "32-bit float",
      "file_format": "GeoTIFF",
      "tile_unit": "Not established in inspected sources",
      "nodata_value": "Not established in inspected sources",
      "accuracy_metric_basis": "Strips unregistered to ground control/altimetry",
      "quality_layers": "Not established in inspected sources",
      "release_strategy": "Dated strip releases; separate mosaics",
      "access_condition": "Public EOCL exception excludes Alaska imagery after June 2022",
      "reuse_condition": "Release/source-specific NextView or EOCL public-release terms",
      "publisher": "PGC / NGA / NSF",
      "source_ids": [
        "S012",
        "S039"
      ],
      "sources": [
        {
          "id": "S012",
          "url": "https://www.pgc.umn.edu/data/arcticdem/",
          "observed_utc": "2026-10-25T00:04:18.622149+00:00",
          "status": "opened",
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        },
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          "url": "https://www.pgc.umn.edu/guides/commercial-imagery/eocl-license-pgc-faq/",
          "observed_utc": "2026-10-25T00:04:21.561645+00:00",
          "status": "opened",
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          "observation_sha256": null
        }
      ],
      "checked_at_utc": "2026-10-25T00:04:21.561645+00:00",
      "licence": "NextView / EOCL public DEM release exception",
      "licence_source_ids": [
        "S039"
      ],
      "licence_checked_at_utc": "2026-10-25T00:04:21.561645+00:00",
      "licence_quote_ids": []
    },
    {
      "record_id": "E05",
      "item_name": "GEBCO 2026 grid",
      "source_url": "https://www.gebco.net/data-products/gridded-bathymetry-data",
      "source_version": "2026",
      "audit_status": "Primary product documentation inspected; no raster accuracy measurement",
      "surface_representation": "Land elevation and bathymetry",
      "geographic_coverage": "Global",
      "grid_spacing": "15 arc-seconds",
      "horizontal_reference": "Not established in inspected sources",
      "vertical_reference": "Assumed mean sea level; some source datums differ",
      "vertical_unit": "Metres",
      "pixel_registration": "Not established in inspected sources",
      "acquisition_period": "Not established in inspected sources",
      "source_sensor": "Multiple measured and interpolated sources",
      "void_fill_sources": "Not established in inspected sources",
      "water_treatment": "Not established in inspected sources",
      "data_type": "Not established in inspected sources",
      "file_format": "netCDF, GeoTIFF and ASCII",
      "tile_unit": "Global grid or regional tiles/subsets",
      "nodata_value": "Not established in inspected sources",
      "accuracy_metric_basis": "Grid spacing is not source-data resolution or accuracy",
      "quality_layers": "Type Identifier source-category grid",
      "release_strategy": "Annual; 2026 edition",
      "access_condition": "Public downloads and subset services",
      "reuse_condition": "Public domain with acknowledgement and use conditions; not navigation",
      "publisher": "GEBCO",
      "source_ids": [
        "S013",
        "S040"
      ],
      "sources": [
        {
          "id": "S013",
          "url": "https://www.gebco.net/data-products/gridded-bathymetry-data",
          "observed_utc": "2026-10-25T00:04:18.723906+00:00",
          "status": "opened",
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          "url": "https://www.gebco.net/data-products/gridded-bathymetry/terms-of-use",
          "observed_utc": "2026-10-25T00:04:21.758765+00:00",
          "status": "opened",
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      ],
      "checked_at_utc": "2026-10-25T00:04:21.758765+00:00",
      "licence": "Public domain (GEBCO terms of use)",
      "licence_source_ids": [
        "S040"
      ],
      "licence_checked_at_utc": "2026-10-25T00:04:21.758765+00:00",
      "licence_quote_ids": []
    },
    {
      "record_id": "E06",
      "item_name": "USGS 3DEP 1/3-arc-second DEM",
      "source_url": "https://www.usgs.gov/3d-elevation-program/about-3dep-products-services",
      "source_version": "Current inspected documentation",
      "audit_status": "Primary product documentation inspected; no raster accuracy measurement",
      "surface_representation": "Bare-earth seamless terrain",
      "geographic_coverage": "CONUS, Alaska, Hawaii and US territories",
      "grid_spacing": "1/3 arc-second; approximately 10 m north–south",
      "horizontal_reference": "NAD83 geographic coordinates",
      "vertical_reference": "Usually NAVD88; local/NGVD29 exceptions outside CONUS",
      "vertical_unit": "Metres",
      "pixel_registration": "Not established in inspected sources",
      "acquisition_period": "Not established in inspected sources",
      "source_sensor": "Best available blended project data",
      "void_fill_sources": "Not established in inspected sources",
      "water_treatment": "Water surfaces flattened",
      "data_type": "Not established in inspected sources",
      "file_format": "GeoTIFF product; file not downloaded",
      "tile_unit": "Standard tiles; inspect selected download metadata",
      "nodata_value": "Not established in inspected sources",
      "accuracy_metric_basis": "Varies by source project; no uniform local value established",
      "quality_layers": "Not established in inspected sources",
      "release_strategy": "Updated as better source projects enter the seamless product",
      "access_condition": "Free public 3DEP downloads",
      "reuse_condition": "3DEP no use restrictions",
      "publisher": "USGS",
      "source_ids": [
        "S006",
        "S051",
        "S058"
      ],
      "sources": [
        {
          "id": "S006",
          "url": "https://www.usgs.gov/3d-elevation-program/about-3dep-products-services",
          "observed_utc": "2026-10-25T00:04:17.874674+00:00",
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          "id": "S051",
          "url": "https://www.usgs.gov/faqs/what-projection-horizontal-datum-vertical-datum-and-resolution-a-usgs-digital-elevation-model",
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          "id": "S058",
          "url": "https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits",
          "observed_utc": "2026-10-25T00:04:24.630854+00:00",
          "status": "opened",
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      ],
      "checked_at_utc": "2026-10-25T00:04:23.874849+00:00",
      "licence": "US public domain (USGS-produced)",
      "licence_source_ids": [
        "S058",
        "S006"
      ],
      "licence_checked_at_utc": "2026-10-25T00:04:24.630854+00:00",
      "licence_quote_ids": []
    },
    {
      "record_id": "E07",
      "item_name": "USGS 3DEP 1-arc-second DEM",
      "source_url": "https://www.usgs.gov/3d-elevation-program/about-3dep-products-services",
      "source_version": "Current inspected documentation",
      "audit_status": "Primary product documentation inspected; no raster accuracy measurement",
      "surface_representation": "Bare-earth seamless terrain",
      "geographic_coverage": "CONUS, Alaska; much of Canada and Mexico",
      "grid_spacing": "1 arc-second; approximately 30 m north–south",
      "horizontal_reference": "NAD83 geographic coordinates",
      "vertical_reference": "Usually NAVD88; local/NGVD29 exceptions outside CONUS",
      "vertical_unit": "Metres",
      "pixel_registration": "Not established in inspected sources",
      "acquisition_period": "Not established in inspected sources",
      "source_sensor": "Best available blended project data",
      "void_fill_sources": "Not established in inspected sources",
      "water_treatment": "Water surfaces flattened",
      "data_type": "Not established in inspected sources",
      "file_format": "GeoTIFF product; file not downloaded",
      "tile_unit": "Standard tiles; inspect selected download metadata",
      "nodata_value": "Not established in inspected sources",
      "accuracy_metric_basis": "Varies by source project; no uniform local value established",
      "quality_layers": "Not established in inspected sources",
      "release_strategy": "Updated as better source projects enter the seamless product",
      "access_condition": "Free public 3DEP downloads",
      "reuse_condition": "3DEP no use restrictions",
      "publisher": "USGS",
      "source_ids": [
        "S006",
        "S051",
        "S058"
      ],
      "sources": [
        {
          "id": "S006",
          "url": "https://www.usgs.gov/3d-elevation-program/about-3dep-products-services",
          "observed_utc": "2026-10-25T00:04:17.874674+00:00",
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        },
        {
          "id": "S051",
          "url": "https://www.usgs.gov/faqs/what-projection-horizontal-datum-vertical-datum-and-resolution-a-usgs-digital-elevation-model",
          "observed_utc": "2026-10-25T00:04:23.874849+00:00",
          "status": "opened",
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          "observation_sha256": null
        },
        {
          "id": "S058",
          "url": "https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits",
          "observed_utc": "2026-10-25T00:04:24.630854+00:00",
          "status": "opened",
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        }
      ],
      "checked_at_utc": "2026-10-25T00:04:23.874849+00:00",
      "licence": "US public domain (USGS-produced)",
      "licence_source_ids": [
        "S058",
        "S006"
      ],
      "licence_checked_at_utc": "2026-10-25T00:04:24.630854+00:00",
      "licence_quote_ids": []
    },
    {
      "record_id": "E08",
      "item_name": "USGS Alaska 5-metre IfSAR DEM",
      "source_url": "https://www.usgs.gov/3d-elevation-program/about-3dep-products-services",
      "source_version": "Current inspected documentation",
      "audit_status": "Primary product documentation inspected; no raster accuracy measurement",
      "surface_representation": "Bare-earth DTM",
      "geographic_coverage": "Alaska",
      "grid_spacing": "5 metres",
      "horizontal_reference": "NAD83 / Alaska Albers",
      "vertical_reference": "Tile metadata required; do not assume CONUS vertical datum",
      "vertical_unit": "Metres",
      "pixel_registration": "Not established in inspected sources",
      "acquisition_period": "Not established in inspected sources",
      "source_sensor": "IfSAR",
      "void_fill_sources": "Not established in inspected sources",
      "water_treatment": "Not established in inspected sources",
      "data_type": "Not established in inspected sources",
      "file_format": "GeoTIFF",
      "tile_unit": "One-degree project blocks with overedge",
      "nodata_value": "Not established in inspected sources",
      "accuracy_metric_basis": "Not established for selected tile",
      "quality_layers": "Not established in inspected sources",
      "release_strategy": "Project-based",
      "access_condition": "EarthExplorer / public 3DEP product access",
      "reuse_condition": "3DEP no use restrictions",
      "publisher": "USGS",
      "source_ids": [
        "S006",
        "S051",
        "S058"
      ],
      "sources": [
        {
          "id": "S006",
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          "url": "https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits",
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      "checked_at_utc": "2026-10-25T00:04:23.874849+00:00",
      "licence": "US public domain (USGS-produced)",
      "licence_source_ids": [
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      "licence_checked_at_utc": "2026-10-25T00:04:24.630854+00:00",
      "licence_quote_ids": []
    },
    {
      "record_id": "E09",
      "item_name": "USGS Alaska IfSAR DSM",
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      "geographic_coverage": "Alaska",
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      "water_treatment": "Not established in inspected sources",
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      "quality_layers": "Not established in inspected sources",
      "release_strategy": "Project-based",
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      "licence": "US public domain (USGS-produced)",
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      "licence_checked_at_utc": "2026-10-25T00:04:24.630854+00:00",
      "licence_quote_ids": []
    },
    {
      "record_id": "E10",
      "item_name": "Copernicus GLO-90",
      "source_url": "https://dataspace.copernicus.eu/explore-data/data-collections/copernicus-contributing-missions/collections-description/COP-DEM",
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      "audit_status": "Primary product documentation inspected; no raster accuracy measurement",
      "surface_representation": "DSM; buildings and vegetation retained",
      "geographic_coverage": "Global",
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      "data_type": "DGED/INSPIRE float32; DTED int16",
      "file_format": "GeoTIFF; DTED where offered",
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      "quality_layers": "Editing/filling/water/error masks and provenance",
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      "access_condition": "GLO-90 registered users",
      "reuse_condition": "Instance-specific source and derivative notices; EEA-10 access restrictions remain",
      "publisher": "ESA / Airbus",
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      "sources": [
        {
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      "licence": "Copernicus DEM ESA–User Licence (instance-specific)",
      "licence_source_ids": [
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      "licence_checked_at_utc": "2026-10-25T00:04:21.110091+00:00",
      "licence_quote_ids": []
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      "item_name": "Copernicus EEA-10",
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      "licence": "Copernicus DEM ESA–User Licence (instance-specific)",
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      "licence_quote_ids": []
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    {
      "record_id": "E12",
      "item_name": "ArcticDEM mosaic",
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      "source_version": "Current inspected documentation",
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      "surface_representation": "DSM mosaic",
      "geographic_coverage": "Arctic; release-specific coverage",
      "grid_spacing": "2 m primary; coarser mosaics also offered",
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      "vertical_unit": "Metres",
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      "acquisition_period": "Multiple strip dates; per-pixel date range",
      "source_sensor": "Optical stereo strips",
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      "water_treatment": "Not established in inspected sources",
      "data_type": "float32",
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      "nodata_value": "Not established in inspected sources",
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      "quality_layers": "Per-pixel dates and product metadata",
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      "access_condition": "Public release; source imagery restriction remains",
      "reuse_condition": "Product acknowledgement; EOCL/NextView release scope",
      "publisher": "PGC / NGA / NSF",
      "source_ids": [
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      "sources": [
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      "licence": "NextView / EOCL public DEM release exception",
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      "quality_layers": "Not established in inspected sources",
      "release_strategy": "Annual strips; current inspected release includes 2024",
      "access_condition": "Public PGC/STAC downloads",
      "reuse_condition": "PGC acknowledgement; public REMA release exception",
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      "sources": [
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      "licence": "NextView / EOCL public DEM release exception",
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      "licence": "CC0 (unmarked NASA-led mission data; check exceptions)",
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