{
  "version": 1,
  "status": "provisional",
  "coordinateConvention": "Original image pixels from top-left. worldX = a*x + c*y + e; worldY = b*x + d*y + f. World units are EPSG:3857 metres, with worldY equal to negative standard Mercator northing so that north is up in screen coordinates.",
  "summary": "Hand-picked geographic controls give approximate shared placement. Independent checks show material local errors; this is not survey-grade alignment. Sources without an accepted placement remain readable as separate scans.",
  "maps": {
    "sheet5": {
      "width": 5187,
      "height": 7245,
      "matrix": [
        1.1584732454352527, 0.07937300766838007, -0.03503914300800837, 1.1553879750570104,
        -9131.98159579801, -6717988.315224167
      ],
      "controls": [
        {
          "name": "St Leonard Shoreditch church block",
          "x": 555,
          "y": 2500,
          "lat": 51.52683443,
          "lon": -0.0774461,
          "coordinateSource": "https://shalt.dmu.ac.uk/locations/st-leonards-the-actors-church.html",
          "pixelUncertainty": 100
        },
        {
          "name": "Christ Church Spitalfields church block",
          "x": 840,
          "y": 3770,
          "lat": 51.5191,
          "lon": -0.07372,
          "coordinateSource": "https://mapcarta.com/W420026096",
          "pixelUncertainty": 120
        },
        {
          "name": "Tower of London inner fortress center",
          "x": 745,
          "y": 5390,
          "lat": 51.50813,
          "lon": -0.07629,
          "coordinateSource": "https://mapcarta.com/24919250",
          "pixelUncertainty": 100
        },
        {
          "name": "St Dunstan Stepney church block",
          "x": 4000,
          "y": 3836,
          "lat": 51.51686,
          "lon": -0.04166,
          "coordinateSource": "https://mapcarta.com/37247290",
          "pixelUncertainty": 150
        }
      ],
      "heldOut": [
        {
          "name": "St George in the East church (uncertain footprint pick)",
          "x": 2180,
          "y": 5300,
          "lat": 51.51004,
          "lon": -0.05973,
          "coordinateSource": "https://mapcarta.com/36465182",
          "residualMetres": 220,
          "pixelUncertainty": 150
        }
      ],
      "fitRmsMetres": 41,
      "residualMetres": 220,
      "quality": "rough; western and eastern points anchor the placement, but held-out church misses by about 220 metres",
      "notes": "The wide overlap with sheet 6 confirms broad placement. Church-label centroids and historical/current footprint differences are material; held-out St George pick is particularly uncertain. Do not use as precise street-level overlay."
    },
    "sheet6": {
      "width": 8125,
      "height": 6675,
      "matrix": [
        1.07963348312244, 0.0069125698427181526, 0.04960982224728827, 1.1375307173436795,
        -16942.706155436033, -6717712.754606128
      ],
      "controls": [
        {
          "name": "King's Cross railway terminus building",
          "x": 2860,
          "y": 1530,
          "lat": 51.53206,
          "lon": -0.12376,
          "coordinateSource": "https://mapcarta.com/17636626",
          "pixelUncertainty": 70
        },
        {
          "name": "British Museum core building",
          "x": 2450,
          "y": 3500,
          "lat": 51.51945,
          "lon": -0.12708,
          "coordinateSource": "https://mapcarta.com/25741402/Map",
          "pixelUncertainty": 50
        },
        {
          "name": "Lincoln's Inn Fields park center",
          "x": 3465,
          "y": 4025,
          "lat": 51.51627,
          "lon": -0.11657,
          "coordinateSource": "https://mapcarta.com/17634648",
          "pixelUncertainty": 70
        },
        {
          "name": "Tower of London inner fortress center",
          "x": 7590,
          "y": 5260,
          "lat": 51.50813,
          "lon": -0.07629,
          "coordinateSource": "https://mapcarta.com/24919250",
          "pixelUncertainty": 100
        }
      ],
      "heldOut": [
        {
          "name": "St Bride's Church",
          "x": 4580,
          "y": 4510,
          "lat": 51.51378,
          "lon": -0.10555,
          "coordinateSource": "https://mapcarta.com/25585430",
          "residualMetres": 84,
          "pixelUncertainty": 70
        }
      ],
      "fitRmsMetres": 14,
      "residualMetres": 84,
      "quality": "approximate; usable for shared city-view placement with visible registration uncertainty",
      "notes": "Four hand-picked dispersed control centers. Held-out St Bride residual is about 84 ground metres. Modern geocoded facility centers and scanned 1899 cartography add uncertainty; this is not a survey-grade georeference. The original asset is byte-identical to scratch/acquisition/boothSheet6.jpg."
    },
    "booth1890": {
      "width": 8114,
      "height": 5978,
      "matrix": [
        6.148328801020218, 0.030342099991685245, -0.09211836373607851, 4.662823057039816,
        -32093.232796101536, -6723420.910950733
      ],
      "controls": [
        {
          "name": "King's Cross railway terminus",
          "x": 3005,
          "y": 1580,
          "lat": 51.53206,
          "lon": -0.12376,
          "coordinateSource": "https://mapcarta.com/17636626",
          "pixelUncertainty": 45
        },
        {
          "name": "British Museum",
          "x": 2945,
          "y": 2070,
          "lat": 51.51945,
          "lon": -0.12708,
          "coordinateSource": "https://mapcarta.com/25741402/Map",
          "pixelUncertainty": 35
        },
        {
          "name": "Tower of London",
          "x": 3875,
          "y": 2495,
          "lat": 51.50813,
          "lon": -0.07629,
          "coordinateSource": "https://mapcarta.com/24919250",
          "pixelUncertainty": 35
        },
        {
          "name": "Waterloo Bridge midpoint",
          "x": 3145,
          "y": 2480,
          "lat": 51.50855,
          "lon": -0.11685,
          "coordinateSource": "https://mapcarta.com/25585498",
          "pixelUncertainty": 35
        }
      ],
      "heldOut": [
        {
          "name": "London Bridge midpoint",
          "x": 3667,
          "y": 2502,
          "lat": 51.50802,
          "lon": -0.08768,
          "coordinateSource": "https://mapcarta.com/25585456",
          "residualMetres": 12,
          "pixelUncertainty": 30
        },
        {
          "name": "Westminster Bridge midpoint (outlier)",
          "x": 3035,
          "y": 2680,
          "lat": 51.50089,
          "lon": -0.12184,
          "coordinateSource": "https://mapcarta.com/25585500/Map",
          "residualMetres": 292,
          "pixelUncertainty": 70
        }
      ],
      "fitRmsMetres": 14,
      "residualMetres": 292,
      "quality": "rough central-London alignment only; one west-side held-out point misses by about 292 metres and map-wide accuracy is untested",
      "notes": "Four visually picked landmarks from the overview, including old Waterloo Bridge on the same crossing alignment as its modern replacement. London Bridge held-out agreement is good, but Westminster Bridge is a material outlier; original-map simplification, picking, and historic/current footprint differences are unresolved. The broad overview covers far more than the central controls; do not claim accurate local overlay at its outer districts."
    },
    "sheet4": {
      "width": 9107,
      "height": 8391,
      "matrix": [
        1.0892770953044568, 0.09429133022240421, -0.002570322225418309, 1.1517979085217576,
        -22755.765599073096, -6723122.479360682
      ],
      "controls": [
        {
          "name": "St Mary with All Souls Kilburn church",
          "x": 1605,
          "y": 4620,
          "lat": 51.5415,
          "lon": -0.1889,
          "coordinateSource": "https://commons.wikimedia.org/wiki/File:St_Mary_with_All_Souls,_Kilburn_-_geograph.org.uk_-_509643.jpg",
          "pixelUncertainty": 50
        },
        {
          "name": "St Peter Belsize Park church",
          "x": 3390,
          "y": 3515,
          "lat": 51.547602,
          "lon": -0.17156414,
          "coordinateSource": "https://casework.jcnas.org.uk/node/107423",
          "pixelUncertainty": 50
        },
        {
          "name": "Christ Church Albany Street building",
          "x": 6180,
          "y": 5980,
          "lat": 51.53026,
          "lon": -0.14434,
          "coordinateSource": "https://mapcarta.com/W40253015",
          "pixelUncertainty": 50
        },
        {
          "name": "Primrose Hill summit vicinity",
          "x": 4388,
          "y": 4772,
          "lat": 51.53934,
          "lon": -0.16102,
          "coordinateSource": "https://mapcarta.com/25726842",
          "pixelUncertainty": 150
        }
      ],
      "heldOut": [
        {
          "name": "London Zoo historic footprint centre versus modern Zoo centre",
          "x": 5100,
          "y": 5550,
          "lat": 51.5353021,
          "lon": -0.1552372,
          "coordinateSource": "https://londinium.com/relation/231792",
          "residualMetres": 182,
          "pixelUncertainty": 180
        }
      ],
      "fitRmsMetres": 28,
      "residualMetres": 182,
      "quality": "rough; church controls fit, but park and zoo centres carry broad footprint ambiguity",
      "notes": "Visual church footprint controls span the sheet. Primrose Hill and Zoo are area-centre proxies rather than exact survey points. Do not interpret the 182 m held-out residual as pure scan error; modern and historical Zoo footprints differ."
    },
    "sheet3": {
      "width": 8442,
      "height": 7211,
      "matrix": [
        1.0778612926266846, -0.041889088551670284, -0.000560754908542016, 1.0824629622736666,
        -16199.69102914398, -6722332.372086748
      ],
      "controls": [
        {
          "name": "King's Cross station twin train sheds",
          "x": 2200,
          "y": 5920,
          "lat": 51.53206,
          "lon": -0.12376,
          "coordinateSource": "https://mapcarta.com/17636626",
          "pixelUncertainty": 60
        },
        {
          "name": "Clissold Park centre",
          "x": 5930,
          "y": 1300,
          "lat": 51.56099,
          "lon": -0.08779,
          "coordinateSource": "https://mapcarta.com/W4481793",
          "pixelUncertainty": 100
        },
        {
          "name": "St Mary's Islington church",
          "x": 4580,
          "y": 5080,
          "lat": 51.53841,
          "lon": -0.10172,
          "coordinateSource": "https://mapcarta.com/36465482",
          "pixelUncertainty": 50
        },
        {
          "name": "Holloway Prison historic footprint centre versus current site",
          "x": 2120,
          "y": 2380,
          "lat": 51.5540083,
          "lon": -0.1253083,
          "coordinateSource": "https://mapcarta.com/W26713924",
          "pixelUncertainty": 120
        }
      ],
      "heldOut": [
        {
          "name": "St Mary Magdalene Holloway Road church building",
          "x": 3880,
          "y": 3350,
          "lat": 51.54839,
          "lon": -0.10791,
          "coordinateSource": "https://mapcarta.com/W27813921",
          "pixelUncertainty": 35,
          "residualMetres": 7
        }
      ],
      "fitRmsMetres": 44,
      "residualMetres": 7,
      "quality": "rough; four broad controls fit, independent church check agrees centrally",
      "notes": "Holloway Prison rebuilt since 1899 and Clissold Park is an area-centre proxy; landmarks are visually inspected but source pixels carry stated uncertainty. An attempted St Mark Dalston church check was rejected because the church footprint could not be pinned unambiguously. Do not imply survey-grade accuracy."
    },
    "sheet2": {
      "width": 7020,
      "height": 6300,
      "matrix": [
        1.0768030085147002, -0.002847644405619576, 0.010089378572258667, 1.0642933425917818,
        -9267.427049583825, -6722386.362946889
      ],
      "controls": [
        {
          "name": "St Matthew Upper Clapton church building",
          "x": 2943,
          "y": 452,
          "lat": 51.56535,
          "lon": -0.05474,
          "coordinateSource": "https://mapcarta.com/W852324309",
          "pixelUncertainty": 25
        },
        {
          "name": "St Mark Dalston church building",
          "x": 1300,
          "y": 3130,
          "lat": 51.5494,
          "lon": -0.07038,
          "coordinateSource": "https://mapcarta.com/W84820250",
          "pixelUncertainty": 25
        },
        {
          "name": "St John at Hackney church building",
          "x": 3075,
          "y": 3190,
          "lat": 51.54909,
          "lon": -0.05324,
          "coordinateSource": "https://mapcarta.com/W368739366",
          "pixelUncertainty": 25
        },
        {
          "name": "St Mary of Eton church building",
          "x": 5400,
          "y": 3815,
          "lat": 51.545394,
          "lon": -0.030661,
          "coordinateSource": "https://historicengland.org.uk/listing/the-list/list-entry/1226605",
          "pixelUncertainty": 35
        }
      ],
      "heldOut": [
        {
          "name": "Hackney Downs park centre",
          "x": 2130,
          "y": 2350,
          "lat": 51.55379,
          "lon": -0.06231,
          "coordinateSource": "https://mapcarta.com/W5993319",
          "pixelUncertainty": 100,
          "residualMetres": 31
        }
      ],
      "fitRmsMetres": 1,
      "residualMetres": 31,
      "quality": "approximate; four surviving churches align closely and park-centre check is within 31 m",
      "notes": "Four visually inspected church footprints span the urban part of the sheet; eastern marsh area remains untested. Source pixels and modern coordinates carry stated uncertainty. The held-out park centre is an area proxy."
    },
    "sheet1": {
      "width": 8031,
      "height": 10000,
      "matrix": [
        1.0718169311650791, 0.004291334586696394, 0.010710492761387691, 1.0923329067250052,
        -7054.52706196829, -6717506.165715173
      ],
      "controls": [
        {
          "name": "St Dunstan Stepney church building",
          "x": 2215,
          "y": 3900,
          "lat": 51.51686,
          "lon": -0.04166,
          "coordinateSource": "https://mapcarta.com/37247290",
          "pixelUncertainty": 35
        },
        {
          "name": "St Anne Limehouse church building",
          "x": 3390,
          "y": 4750,
          "lat": 51.51168,
          "lon": -0.0303,
          "coordinateSource": "https://mapcarta.com/37247466",
          "pixelUncertainty": 30
        },
        {
          "name": "St Matthias Old Church Poplar building",
          "x": 4855,
          "y": 5090,
          "lat": 51.5095,
          "lon": -0.0161,
          "coordinateSource": "https://gb.britishlistedbuildings.co.uk/101065793-church-of-st-matthias-poplar-ward",
          "pixelUncertainty": 35
        },
        {
          "name": "All Saints Poplar church building",
          "x": 5330,
          "y": 4935,
          "lat": 51.5105,
          "lon": -0.0116,
          "coordinateSource": "https://historicengland.org.uk/listing/the-list/list-entry/1240311",
          "pixelUncertainty": 35
        }
      ],
      "heldOut": [
        {
          "name": "Historic St Mary Bow church footprint versus Bow Churchyard point",
          "x": 4810,
          "y": 1885,
          "lat": 51.5284321,
          "lon": -0.0181621,
          "coordinateSource": "https://www.parksandgardens.org/places/bow-churchyard",
          "pixelUncertainty": 150,
          "residualMetres": 117
        }
      ],
      "fitRmsMetres": 4,
      "residualMetres": 117,
      "quality": "rough; four surviving church buildings align within about 20 m, northern held-out Bow churchyard proxy differs about 117 m",
      "notes": "The controls cluster in the central Poplar-Stepney band. The historic St Mary Bow building was destroyed, so the held-out modern churchyard coordinate is a site proxy rather than a matching building point. Rotherhithe and Isle of Dogs extent remain untested; do not imply survey-grade accuracy."
    },
    "ogilbyMorgan1677": {
      "id": "ogilbyMorgan1677",
      "imageType": "plan",
      "sourcePath": "products/sites/londonwebcam.co.uk/src/assets/historicMaps/earlyAtlas/ogilbyMorgan1677.jpg",
      "sourceDimensions": {
        "width": 4000,
        "height": 2366
      },
      "status": "affine-calibrated",
      "matrix": [
        1.2335978175, 0.0515193814, -0.22887487, 1.402028062, -12535.842294, -6714886.611141
      ],
      "controls": [
        {
          "name": "St Paul's Cathedral centre, Old St Paul's footprint",
          "x": 1599,
          "y": 1624,
          "lat": 51.51372,
          "lon": -0.09835,
          "pixelMethod": "Visually selected centre of the labeled St Paul's Cathedral footprint on the original-resolution scan.",
          "coordinateSource": "Shared registration coordinate catalogue supplied by registration_review"
        },
        {
          "name": "London Bridge midpoint",
          "x": 2660,
          "y": 2210,
          "lat": 51.50802,
          "lon": -0.08768,
          "pixelMethod": "Visually selected midpoint of the labeled bridge crossing on the original-resolution scan.",
          "coordinateSource": "Shared registration coordinate catalogue supplied by registration_review"
        },
        {
          "name": "Tower of London centre",
          "x": 3670,
          "y": 2130,
          "lat": 51.50813,
          "lon": -0.07629,
          "pixelMethod": "Visually selected centre of the Tower enclosure on the original-resolution scan.",
          "coordinateSource": "Shared registration coordinate catalogue supplied by registration_review"
        },
        {
          "name": "St Bride's Church centre",
          "x": 900,
          "y": 1460,
          "lat": 51.51378,
          "lon": -0.10555,
          "pixelMethod": "Visually selected church footprint identified by its printed label on the original-resolution scan.",
          "coordinateSource": "Shared registration coordinate catalogue supplied by registration_review"
        }
      ],
      "residualsMetres": {
        "perControl": {
          "St Paul's Cathedral centre, Old St Paul's footprint": 146.16,
          "London Bridge midpoint": 2.29,
          "Tower of London centre": 38.34,
          "St Bride's Church centre": 110.11
        },
        "rms": 93.49,
        "maximum": 146.16
      },
      "quality": "Medium. Four visually matched landmarks support a useful approximate city-scale affine, with 93.49 m RMS and 146.16 m maximum fit residual. The 1677 plan is a reduced facsimile scan, and landmark centres/geographic coordinates are approximate; no independent fifth landmark was available for a hold-out test.",
      "notes": "Visually checked as a north-up street plan. Calibration is approximate and intended for broad historical comparison, not parcel-level georeferencing."
    },
    "londonAndEnvirons1761": {
      "id": "londonAndEnvirons1761",
      "imageType": "plan",
      "sourcePath": "products/sites/londonwebcam.co.uk/src/assets/historicMaps/earlyAtlas/londonAndEnvirons1761.jpg",
      "sourceDimensions": {
        "width": 7300,
        "height": 4121
      },
      "status": "affine-calibrated",
      "matrix": [
        1.5411006084, -0.0920470184, 0.0252054479, 1.5149757062, -17797.12483, -6714970.636305
      ],
      "controls": [
        {
          "name": "St Paul's Cathedral centre",
          "x": 4410,
          "y": 1780,
          "lat": 51.51372,
          "lon": -0.09835,
          "pixelMethod": "Visually selected centre of the labeled cathedral footprint on the original-resolution plan.",
          "coordinateSource": "Shared registration coordinate catalogue supplied by registration_review"
        },
        {
          "name": "London Bridge midpoint",
          "x": 5230,
          "y": 2560,
          "lat": 51.50802,
          "lon": -0.08768,
          "pixelMethod": "Visually selected midpoint of the labeled bridge crossing on the original-resolution plan.",
          "coordinateSource": "Shared registration coordinate catalogue supplied by registration_review"
        },
        {
          "name": "Tower of London centre",
          "x": 5955,
          "y": 2500,
          "lat": 51.50813,
          "lon": -0.07629,
          "pixelMethod": "Visually selected centre of the Tower enclosure on the original-resolution plan.",
          "coordinateSource": "Shared registration coordinate catalogue supplied by registration_review"
        },
        {
          "name": "Westminster Bridge midpoint",
          "x": 2685,
          "y": 3185,
          "lat": 51.50089,
          "lon": -0.12184,
          "pixelMethod": "Visually selected midpoint of the labeled bridge crossing on the original-resolution plan.",
          "coordinateSource": "Shared registration coordinate catalogue supplied by registration_review"
        }
      ],
      "residualsMetres": {
        "perControl": {
          "St Paul's Cathedral centre": 10.44,
          "London Bridge midpoint": 118.59,
          "Tower of London centre": 86.79,
          "Westminster Bridge midpoint": 21.36
        },
        "rms": 74.43,
        "maximum": 118.59,
        "heldOut": {
          "name": "Lincoln's Inn Fields centre",
          "x": 3210,
          "y": 1460,
          "lat": 51.51627,
          "lon": -0.11657,
          "residualMetres": 179.45,
          "pixelMethod": "Visually selected centre of the clearly labeled Lincoln's Inn Fields enclosure on the original-resolution plan.",
          "coordinateSource": "Shared registration coordinate catalogue supplied by registration_review"
        }
      },
      "quality": "Medium-high for broad city-scale comparison. Four control landmarks yield 74.43 m RMS and 118.59 m maximum fit residual; a fifth visually identified landmark held out from fitting is 179.45 m away. The plan and all point centres are historical/scan approximations, so this is not a parcel-level registration.",
      "notes": "Visually checked as a north-oriented plan titled A New and Correct Plan of London, Westminster and Southwark. The fit uses four independent controls and an independent Lincoln's Inn Fields hold-out."
    },
    "crutchley1848": {
      "matrix": [
        3.9915639841390345, 0.26806660517058845, 0.05873733258523117, 3.9053786397644217,
        -20605.383600892867, -6717718.988234277
      ],
      "controls": [
        {
          "name": "Regents Park Botanic Garden",
          "pixel": [833.3, 556.3],
          "lonLat": [-0.1549, 51.5287],
          "residualMetres": 30.0
        },
        {
          "name": "Lincolns Inn Fields",
          "pixel": [1895.8, 1027.2],
          "lonLat": [-0.11657, 51.51627],
          "residualMetres": 70.2
        },
        {
          "name": "St Pauls Cathedral",
          "pixel": [2406.2, 1123.0],
          "lonLat": [-0.09835, 51.51385],
          "residualMetres": 15.5
        },
        {
          "name": "Tower of London",
          "pixel": [3012.5, 1348.1],
          "lonLat": [-0.07629, 51.50813],
          "residualMetres": 27.9
        },
        {
          "name": "Westminster Abbey",
          "pixel": [1583.3, 1839.8],
          "lonLat": [-0.12736, 51.49942],
          "residualMetres": 5.9
        }
      ],
      "heldOut": [
        {
          "name": "Westminster Bridge",
          "pixel": [1725.0, 1764.8],
          "lonLat": [-0.12184, 51.50089],
          "residualMetres": 54.9
        },
        {
          "name": "Waterloo Bridge",
          "pixel": [1866.7, 1391.8],
          "lonLat": [-0.11685, 51.50855],
          "residualMetres": 73.7
        }
      ],
      "residualMetres": {
        "trainingMax": 70.2,
        "heldOutMax": 73.7
      },
      "quality": "rough geographic alignment; usable for shared city-view placement with visible registration uncertainty",
      "notes": "Five visually identified, spatially dispersed landmark centres. Abbey, cathedral and Tower are building-centre picks; Regent garden and Lincoln park are area-centre picks. Garden coordinate approximate. Source pixels scaled from overview and checked against source-resolution crops. Westminster and Waterloo held-out bridge centres use the coordinate catalogue in calibrationBooth.json. The east Thames bridge previously called London Bridge was not confidently identified and was excluded. Historical print and scan distortion remain; not a street-level survey.",
      "recommendedForIntegration": true,
      "sourceDimensions": [4000, 2842],
      "status": "accepted"
    },
    "cruchley1849": {
      "matrix": [
        4.293941643103946, 0.075437663589355, 0.4159856074683326, 4.432551028650323,
        -20755.94971707925, -6717774.699616195
      ],
      "controls": [
        {
          "name": "Regents Park Botanic Garden",
          "pixel": [765.6, 536.5],
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          "residualMetres": 14.2
        },
        {
          "name": "Lincolns Inn Fields",
          "pixel": [1708.3, 1005.3],
          "lonLat": [-0.11657, 51.51627],
          "residualMetres": 66.0
        },
        {
          "name": "St Pauls Cathedral",
          "pixel": [2187.5, 1119.9],
          "lonLat": [-0.09835, 51.51385],
          "residualMetres": 71.9
        },
        {
          "name": "Tower of London",
          "pixel": [2721.4, 1328.2],
          "lonLat": [-0.07629, 51.50813],
          "residualMetres": 26.9
        },
        {
          "name": "Westminster Abbey",
          "pixel": [1367.2, 1705.9],
          "lonLat": [-0.12736, 51.49942],
          "residualMetres": 5.7
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      ],
      "heldOut": [
        {
          "name": "Westminster Bridge",
          "pixel": [1562.5, 1633.0],
          "lonLat": [-0.12184, 51.50089],
          "residualMetres": 199.9
        },
        {
          "name": "Waterloo Bridge",
          "pixel": [1699.2, 1341.3],
          "lonLat": [-0.11685, 51.50855],
          "residualMetres": 115.9
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      ],
      "residualMetres": {
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        "heldOutMax": 199.9
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      "quality": "rough geographic alignment; usable for shared city-view placement with visible registration uncertainty",
      "notes": "Five visually identified, spatially dispersed landmark centres. Abbey, cathedral and Tower are building-centre picks; Regent garden and Lincoln park are area-centre picks. Garden coordinate approximate. Source pixels scaled from overview and checked against source-resolution crops. Westminster and Waterloo held-out bridge centres use the coordinate catalogue in calibrationBooth.json. The east Thames bridge previously called London Bridge was not confidently identified and was excluded. Historical print and scan distortion remain; not a street-level survey.",
      "recommendedForIntegration": true,
      "sourceDimensions": [5000, 2607],
      "status": "accepted"
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    "smith1910": {
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        {
          "name": "British Museum",
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        {
          "name": "Hyde Park Corner",
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      "heldOut": [
        {
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        {
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        {
          "name": "Blackfriars Bridge",
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      ],
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      "quality": "rough geographic alignment; visually checked crossings, but 250-300 m local error",
      "notes": "Five dispersed centres: Botanic Garden, British Museum, Hyde Park Corner, Abbey, Tower. Three bridge holdouts visually checked in source crop. Bridge sequence is Westminster, Waterloo, Blackfriars; earlier candidate mislabeled Blackfriars as Waterloo and has been superseded. Approximate historic map registration for shared city view, not precise street overlay.",
      "recommendedForIntegration": true,
      "sourceDimensions": [5000, 3399],
      "status": "accepted"
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    "warperLondon1815": {
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      "georeferencedExport": true,
      "controlPointStatus": "Community-created Wikimaps Warper control points; not independently surveyed or audited.",
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      "auxXmlUrl": "https://warper.wmflabs.org/maps/4434/export.aux_xml",
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      "cornerPixelCoordinates": [
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        [9612, 3976],
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      "webMercatorMatrixNote": "Local linearization at map-center latitude from the EPSG:4326 GeoTransform; latitude-to-Mercator northing is nonlinear. Prefer row/mesh reprojection using geoTransformLonLat for exact placement.",
      "matrix": [
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      "geographicRaster": [
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      "notes": "Display reprojects each latitude band to the shared Web Mercator camera; the PNG/JPEG raster is a rectified derivative, not a raw historical original."
    },
    "warperDavies1852": {
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      "sourceCrs": "EPSG:4326",
      "georeferencedExport": true,
      "controlPointStatus": "Community-created Wikimaps Warper control points; not independently surveyed or audited.",
      "warperMetadataUrl": "https://warper.wmflabs.org/api/v1/maps/4436",
      "auxXmlUrl": "https://warper.wmflabs.org/maps/4436/export.aux_xml",
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      "webMercatorMatrixNote": "Local linearization at map-center latitude from the EPSG:4326 GeoTransform; latitude-to-Mercator northing is nonlinear. Prefer row/mesh reprojection using geoTransformLonLat for exact placement.",
      "matrix": [
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      "geographicRaster": [
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      "notes": "Display reprojects each latitude band to the shared Web Mercator camera; the PNG/JPEG raster is a rectified derivative, not a raw historical original."
    },
    "warperTollgates1801": {
      "warperMapId": 5955,
      "sourceCrs": "EPSG:4326",
      "georeferencedExport": true,
      "controlPointStatus": "Community-created Wikimaps Warper control points; not independently surveyed or audited.",
      "warperMetadataUrl": "https://warper.wmflabs.org/api/v1/maps/5955",
      "auxXmlUrl": "https://warper.wmflabs.org/maps/5955/export.aux_xml",
      "gcpsCsvUrl": "https://warper.wmflabs.org/maps/5955/gcps.csv",
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      "cornerPixelCoordinates": [
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        [0, 0, 1]
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      "webMercatorMatrixNote": "Local linearization at map-center latitude from the EPSG:4326 GeoTransform; latitude-to-Mercator northing is nonlinear. Prefer row/mesh reprojection using geoTransformLonLat for exact placement.",
      "matrix": [
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      "geographicRaster": [
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        -0.0001440357432334182
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      "quality": "Community-rectified geographic raster; source control points have not been independently surveyed.",
      "notes": "Display reprojects each latitude band to the shared Web Mercator camera; the PNG/JPEG raster is a rectified derivative, not a raw historical original."
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  }
}