{
  "version": 1,
  "checked": "2026-10-17",
  "scope": "Frankfurt 2 km pilot; research and data comparison registry; no external photos bundled",
  "used": [
    {
      "id": "osm",
      "source": "https://wiki.openstreetmap.org/wiki/Tag:man_made=bridge",
      "license": "ODbL-1.0",
      "local": "data/bridges.json",
      "supports": [
        "location",
        "outline",
        "carried-ways",
        "some-widths",
        "some-structural-types"
      ],
      "doesNotEstablish": [
        "deck-elevation",
        "all-pier-positions",
        "verified-material-colours"
      ]
    },
    {
      "id": "khp-holbeinsteg",
      "source": "https://khp-ing.de/portfolio_page/holbeinsteg/",
      "use": "Project facts and visual reference; no site photographs redistributed",
      "facts": {
        "mainSpanMetres": 142,
        "totalLengthMetres": 210,
        "pylonHeightMetres": 32.7,
        "pylonForm": "A",
        "riverPiers": 0
      },
      "comparison": "OSM axis 213.43 m differs from published overall length; retain OSM position and 142 m main span"
    },
    {
      "id": "city-eiserner-steg",
      "source": "https://frankfurt.de/themen/kultur/baukultur/kulturdenkmale-und-denkxweb/eiserner-steg",
      "use": "Structural description and reference only",
      "facts": {
        "riverPiers": 2,
        "structure": "iron-truss"
      }
    },
    {
      "id": "heritage-eiserner-steg",
      "source": "https://denkxweb.denkmalpflege-hessen.de/153763/",
      "use": "Identity and historical structural classification",
      "facts": {
        "currentStructuralPrinciple": "cantilever"
      }
    },
    {
      "id": "chm-alte-bruecke",
      "source": "https://chm.de/wp-content/uploads/2019/11/DE_ALTEBR.pdf",
      "use": "Architect project facts; no PDF or photograph bundled",
      "facts": {
        "structure": "stone-approaches-and-central-steel-span"
      }
    },
    {
      "id": "untermain-history",
      "source": "https://chmtexte.de/media/150_jahre_brueckenbauten.pdf",
      "use": "Published construction history as structural reference",
      "facts": {
        "structure": "steel-concrete-composite-on-historic-piers"
      }
    }
  ],
  "availableForNextMeasurementStage": [
    {
      "id": "hvbg-dom1",
      "source": "https://opendata.hessen.de/de/dataset/oberflachenmodell-dom-1",
      "product": "DOM1",
      "licenseFromCatalog": "DL-DE-ZERO-2.0",
      "usedNow": false,
      "purpose": [
        "upper-deck-elevation",
        "height-profile"
      ],
      "limitations": [
        "vegetation-and-superstructure-occlusion",
        "capture-date",
        "does-not-reliably-reveal-undersides"
      ]
    },
    {
      "id": "hvbg-dop20",
      "source": "https://hvbg.hessen.de/landesvermessung/geotopographie/luftbilder",
      "metadata": "https://www.distributions.informationgrid.eu/trefferanzeige?docuuid=89e00640-43a0-9896-101c-1d0c324f7ecb",
      "product": "DOP20",
      "licenseFromMetadata": "DL-DE-ZERO-2.0",
      "usedNow": false,
      "purpose": [
        "deck-width",
        "axis-alignment",
        "pier-or-pylon-plan-position"
      ],
      "limitations": [
        "perspective-and-occlusion",
        "capture-date",
        "product-license-and-version-must-be-captured-at-import"
      ]
    },
    {
      "id": "hvbg-als",
      "source": "https://hvbg.hessen.de/geoinformation/open-data",
      "product": "Airborne Laserscanning",
      "usedNow": false,
      "purpose": [
        "classifiable-3d-measurements",
        "deck-height-validation"
      ],
      "limitations": [
        "not-a-complete-under-bridge-scan",
        "check-product-license-and-data-classification-at-import"
      ]
    },
    {
      "id": "owner-plans",
      "source": "https://frankfurt.de/-/media/frankfurtde/service-und-rathaus/verwaltung/amtsblatt/pdf/amtsblatt/amtsblatt-2023/regulaere-ausgaben-2023/ab2023_nr_37.pdf",
      "usedNow": false,
      "purpose": [
        "as-built-dimensions",
        "bridge-inventory-and-inspection-records"
      ],
      "availability": "No openly licensed full bridge-book or as-built-plan dataset established in this research; request would need separate access and reuse terms"
    }
  ]
}