{
  "title": "Călărași 1852 plan: provisional city-scale registration",
  "status": "approximate_city_scale_only",
  "source_plan": "src/assets/plan-1852.webp",
  "osm_source": "research/raw/osm.json",
  "osm_snapshot": "2026-07-28T02:16:18Z",
  "projection": {
    "name": "local equirectangular plane",
    "origin_lon_lat": [
      27.3333,
      44.2
    ],
    "x_east_m": "(lon - 27.3333) * 111320 * cos(44.2 degrees)",
    "y_north_m": "(lat - 44.2) * 110574"
  },
  "image_to_world_transform": {
    "equation": "[east_m, north_m] = [u_px, v_px] @ matrix + translation",
    "matrix_m_per_px": [
      [
        0.84451334,
        -0.6689217
      ],
      [
        -0.59244616,
        -1.01684686
      ]
    ],
    "translation_m": [
      -328.406,
      286.129
    ],
    "image_size_px": [
      1497,
      1123
    ],
    "basis_lengths_m_per_px": [
      1.0773,
      1.1768
    ],
    "determinant_m2_per_px2": -1.255041,
    "fit_method": "least-squares affine fit to three municipal-history-named present-day boundary streets, sampled by normalized route length",
    "route_sample_count": 40
  },
  "boundary_routes": {
    "Viitor": {
      "osm_way_ids": [
        36949410
      ],
      "source_boundary_px": [
        [
          23.0,
          344.0
        ],
        [
          742.0,
          339.0
        ],
        [
          1295.0,
          198.0
        ]
      ]
    },
    "Gheorghe Lazăr": {
      "osm_way_ids": [
        34904573
      ],
      "source_boundary_px": [
        [
          23.0,
          344.0
        ],
        [
          26.0,
          882.0
        ]
      ]
    },
    "Portului": {
      "osm_way_ids": [
        1422870070,
        40349356
      ],
      "source_boundary_px": [
        [
          1295.0,
          198.0
        ],
        [
          1410.0,
          754.0
        ]
      ]
    }
  },
  "fit_residuals_m": {
    "Viitor": {
      "n": 40,
      "rms_m": 20.31,
      "p90_m": 26.73,
      "p95_m": 32.59,
      "max_m": 38.49
    },
    "Gheorghe Lazăr": {
      "n": 40,
      "rms_m": 24.2,
      "p90_m": 36.6,
      "p95_m": 38.54,
      "max_m": 41.01
    },
    "Portului": {
      "n": 40,
      "rms_m": 19.31,
      "p90_m": 27.4,
      "p95_m": 28.69,
      "max_m": 30.51
    }
  },
  "leave_one_boundary_route_out_m": {
    "Viitor": {
      "n": 40,
      "rms_m": 25.13,
      "p90_m": 33.56,
      "p95_m": 35.19,
      "max_m": 36.32
    },
    "Gheorghe Lazăr": {
      "n": 40,
      "rms_m": 68.73,
      "p90_m": 111.84,
      "p95_m": 118.37,
      "max_m": 124.64
    },
    "Portului": {
      "n": 40,
      "rms_m": 92.29,
      "p90_m": 136.79,
      "p95_m": 141.82,
      "max_m": 147.06
    }
  },
  "mapped_named_corners": {
    "north_west": {
      "image_px": [
        23,
        344
      ],
      "matched_osm_xy_m": [
        -508.23,
        -117.27
      ],
      "joint_fit_xy_m": [
        -512.78,
        -79.05
      ],
      "fit_residual_m": 38.49,
      "fit_support": "included in its boundary polyline"
    },
    "north_east": {
      "image_px": [
        1295,
        198
      ],
      "matched_osm_xy_m": [
        639.2,
        -758.92
      ],
      "joint_fit_xy_m": [
        647.93,
        -781.46
      ],
      "fit_residual_m": 24.17,
      "fit_support": "included in its boundary polyline"
    },
    "south_west": {
      "image_px": [
        26,
        882
      ],
      "matched_osm_xy_m": [
        -833.99,
        -587.41
      ],
      "joint_fit_xy_m": [
        -828.99,
        -628.12
      ],
      "fit_residual_m": 41.01,
      "fit_support": "included in its boundary polyline"
    },
    "south_east": {
      "image_px": [
        1410,
        754
      ],
      "matched_osm_xy_m": [
        409.06,
        -1453.54
      ],
      "joint_fit_xy_m": [
        415.65,
        -1423.75
      ],
      "fit_residual_m": 30.51,
      "fit_support": "included in its boundary polyline"
    }
  },
  "corner_leave_one_route_out": {
    "north_west": {
      "withheld_boundary_route": "Viitor",
      "target_xy_m": [
        -508.23,
        -117.27
      ],
      "prediction_xy_m": [
        -514.95,
        -81.58
      ],
      "holdout_error_m": 36.32
    },
    "north_east": {
      "withheld_boundary_route": "Viitor",
      "target_xy_m": [
        639.2,
        -758.92
      ],
      "prediction_xy_m": [
        648.18,
        -793.77
      ],
      "holdout_error_m": 35.98
    },
    "south_west": {
      "withheld_boundary_route": "Gheorghe Lazăr",
      "target_xy_m": [
        -833.99,
        -587.41
      ],
      "prediction_xy_m": [
        -806.5,
        -708.98
      ],
      "holdout_error_m": 124.64
    },
    "south_east": {
      "withheld_boundary_route": "Portului",
      "target_xy_m": [
        409.06,
        -1453.54
      ],
      "prediction_xy_m": [
        395.24,
        -1307.13
      ],
      "holdout_error_m": 147.06
    }
  },
  "independent_holdout": {
    "name": "plan B old-church marker vs OSM Biserica Sfântul Nicolae building",
    "plan_marker_px": [
      1048.0,
      667.0
    ],
    "osm_way_id": 271863128,
    "osm_building_centroid_xy_m": [
      180.59,
      -1055.75
    ],
    "transformed_marker_xy_m": [
      161.48,
      -1093.14
    ],
    "distance_m": 41.98,
    "used_in_fit": false,
    "qualification": "A present-day church-site correspondence, not proof of building continuity."
  },
  "footprint_outline": {
    "coordinate_order": "local east/north metres",
    "image_boundary_px": [
      [
        23,
        344
      ],
      [
        742,
        339
      ],
      [
        1295,
        198
      ],
      [
        1410,
        754
      ],
      [
        1326,
        797
      ],
      [
        1270,
        829
      ],
      [
        746,
        907
      ],
      [
        26,
        882
      ]
    ],
    "world_xy_m": [
      [
        -512.78,
        -79.05
      ],
      [
        97.38,
        -554.92
      ],
      [
        647.93,
        -781.46
      ],
      [
        415.65,
        -1423.75
      ],
      [
        319.24,
        -1411.29
      ],
      [
        252.99,
        -1406.37
      ],
      [
        -235.75,
        -1135.17
      ],
      [
        -828.99,
        -628.12
      ]
    ],
    "qualification": "Approximate outer planned-town extent from the visible sheet; southern edge follows historic water/boundary marks and is not asserted to match today’s shoreline."
  },
  "visualization_guidance": {
    "conservative_display_band_m": 150,
    "band_type": "conservative visualization buffer, not a statistical confidence interval",
    "use": "city-scale footprint/context only",
    "do_not_use_for": [
      "parcel ownership",
      "lot numbering",
      "quarter polygons",
      "street-to-parcel attribution",
      "survey-grade boundary placement"
    ],
    "central_street_overlay": "withheld; raster-scored internal alignments were unstable and are not part of this registration."
  }
}