{
  "protocol_schema": "abel.tv/reproducible-geometry-calculation/v1",
  "calculation_date_utc": "2026-09-07",
  "model": {
    "name": "WGS-84 ellipsoid",
    "distance": "shortest geodesic distance on the reference ellipsoid",
    "semi_major_axis_m": 6378137,
    "flattening": 0.0033528106647474805,
    "algorithm_implementation": "GeographicLib-JS geodesic routines (Karney)",
    "implementation_version": "1.52.2",
    "implementation_source": "https://www.npmjs.com/package/geographiclib/v/1.52.2",
    "vendored_runtime": "scripts/vendor/geographiclib-1.52.2.cjs",
    "vendored_license": "MIT",
    "javascript_runtime_observed": "v24.13.0",
    "numeric_type": "ECMAScript Number (IEEE 754 binary64)"
  },
  "inputs": {
    "coordinate_order": "lat, lon (decimal degrees)",
    "phi_expression": "(1 + sqrt(5)) / 2",
    "phi": 1.618033988749895,
    "points": {
      "A": {
        "lat": 48.1298883,
        "lon": 11.5630098,
        "label": "Frauenklinik Maistraße 11, Kartenreferenzpunkt",
        "historicalRoomVerified": false,
        "provenance": "Draft specification section 5; current map reference point"
      },
      "B": {
        "lat": 48.3992078,
        "lon": 9.9850548,
        "label": "Einsteins ehemalige Geburtsadresse Bahnhofstraße 20, Kartenreferenzpunkt",
        "historicalRoomVerified": false,
        "provenance": "Draft specification section 5; current map reference point"
      },
      "C": {
        "lat": 49.491333,
        "lon": 8.177017,
        "label": "Trump-Haus, verwendeter Referenzpunkt",
        "provenance": "Draft specification section 5; regular house reference point"
      },
      "P": {
        "lat": 49.49561483929369,
        "lon": 8.17316,
        "label": "Berechneter Kontrollpunkt des Phi-Lokus innerhalb Kallstadts",
        "provenance": "Draft specification section 5; numerical control point"
      }
    }
  },
  "results": {
    "distances": {
      "AB_m": 120916.7216444262,
      "CA_m": 291115.0812981007,
      "CB_m": 179690.0470950166,
      "PA_m": 291595.5387521508,
      "PB_m": 180215.95391666543,
      "CP_m": 552.1474053575341
    },
    "C_ratio_CA_over_CB": 1.620095748231201,
    "P_ratio_PA_over_PB": 1.6180339887499025,
    "P_ratio_error_from_phi": 7.549516567451064e-15,
    "side_order_check_PA_gt_PB_gt_AB": true,
    "C_is_not_phi_with_0_001_tolerance": true,
    "P_inside_current_mapped_Kallstadt_municipality": true
  },
  "municipality_source": {
    "provider": "OpenStreetMap contributors",
    "relation_id": 1249949,
    "relation_name": "Kallstadt",
    "admin_level": "8",
    "relation_version": 10,
    "relation_timestamp": "2021-07-29T05:23:47Z",
    "relation_changeset": 108792217,
    "overpass_generator": "Overpass API 0.7.62.11 87bfad18",
    "overpass_osm_base_timestamp": "2026-09-07T01:01:34Z",
    "retrieval_date_utc": "2026-09-07",
    "retrieval_endpoint": "https://overpass-api.de/api/interpreter",
    "query": "[out:json][timeout:60];relation(1249949);out meta geom;",
    "source_url": "https://www.openstreetmap.org/relation/1249949",
    "snapshot_file": "osm-relation-1249949-overpass-2026-09-07.json",
    "snapshot_sha256": "4926800ab456e184e727376a6f0f1c4f0596c624a1d9f49fa9ff814847187cb1",
    "attribution": "© OpenStreetMap contributors",
    "license": "Open Database License (ODbL) 1.0",
    "license_url": "https://www.openstreetmap.org/copyright",
    "scope_limit": "Current mapped administrative geometry; no claim about the 1869 boundary or a historic birthplace."
  },
  "geometry_processing": {
    "source_coordinate_order": "{lat, lon}",
    "geojson_coordinate_order": "[longitude, latitude]",
    "outer_rings": 3,
    "inner_rings": 0,
    "all_rings_closed": true,
    "inner_assignment": "Each reconstructed inner ring is assigned to the smallest containing outer ring.",
    "locus_method": "Bisection root solve of the signed ratio residual for each longitude; no equality raster search.",
    "locus_longitude_extent": [
      8.12,
      8.2
    ],
    "locus_vertices": 673,
    "locus_spacing_m": {
      "min": 9.887936768703817,
      "max": 10.237353945300034,
      "mean": 10.056915032908032
    },
    "locus_maximum_absolute_ratio_error": 1.7985612998927536e-14
  }
}