Unable to convert scaled value (2147483648) to int32 for dimension 'Y'

[wonder-sk]

Originally reported as a bug in QGIS: qgis/QGIS#49317

When processing a particular LAS file, untwine gets to 99% and then crashes with this output:

Exception: Unable to convert scaled value (2147483648) to int32 for dimension 'Y' when writing LAS/LAZ file.
Exception: Unable to convert scaled value (2147483648) to int32 for dimension 'Y' when writing LAS/LAZ file.

Not sure if the file can be publicly shared, link available on request.

The value 2147483648 is equal to 2^32, so it makes sense that it does not fit to int32 value, but if the scaling is unchanged, there must be something wrong as the original value must have fitted to int32...

The scaling of x/y/z looks a bit suspicious to me (~1e-8)

CloudCompare opens the file without any errors.

Metadata:

$ pdal info --metadata antea_Model_1.las
{
  "filename": "antea_Model_1.las",
  "metadata":
  {
    "comp_spatialreference": "",
    "compressed": false,
    "count": 53773852,
    "creation_doy": 192,
    "creation_year": 2022,
    "dataformat_id": 2,
    "dataoffset": 227,
    "filesource_id": 0,
    "global_encoding": 0,
    "global_encoding_base64": "AAA=",
    "header_size": 227,
    "major_version": 1,
    "maxx": 204.300354,
    "maxy": 22.56153297,
    "maxz": 23.07263947,
    "minor_version": 2,
    "minx": -26.83881378,
    "miny": -60.2872963,
    "minz": -5.98761034,
    "offset_x": 88.730770111084,
    "offset_y": -18.8628816604614,
    "offset_z": 8.54251456260681,
    "point_length": 26,
    "project_id": "9D103B86-4A52-4548-AA16-D86D5E37BB36",
    "scale_x": 5.38162812342115e-08,
    "scale_y": 1.92897462537486e-08,
    "scale_z": 6.76611667009598e-09,
    "software_id": "CaptureReality",
    "spatialreference": "",
    "srs":
    {
      "compoundwkt": "",
      "horizontal": "",
      "isgeocentric": false,
      "isgeographic": false,
      "prettycompoundwkt": "",
      "prettywkt": "",
      "proj4": "",
      "units":
      {
        "horizontal": "unknown",
        "vertical": ""
      },
      "vertical": "",
      "wkt": ""
    },
    "system_id": "Microsoft Windows"
  },
  "pdal_version": "2.0.1 (git-version: Release)"
}

pdal info with stats:

$ pdal info antea_Model_1.las                                                            
{
  "filename": "antea_Model_1.las",
  "pdal_version": "2.0.1 (git-version: Release)",
  "stats":
  {
    "bbox":
    {
      "native":
      {
        "bbox":
        {
          "maxx": 204.300354,
          "maxy": 22.56153297,
          "maxz": 23.07263947,
          "minx": -26.83881378,
          "miny": -60.2872963,
          "minz": -5.98761034
        },
        "boundary": "{ \"type\": \"Polygon\", \"coordinates\": [ [ [ -26.838813781738281, -60.287296295166016, -5.987610340118408 ], [ -26.838813781738281, 22.561532974243164, -5.987610340118408 ], [ 204.30035400390625, 22.561532974243164, 23.072639465332031 ], [ 204.30035400390625, -60.287296295166016, 23.072639465332031 ], [ -26.838813781738281, -60.287296295166016, -5.987610340118408 ] ] ] }"
      }
    },
    "statistic":
    [
      {
        "average": 2.120140667,
        "count": 53773852,
        "maximum": 204.300354,
        "minimum": -26.83881378,
        "name": "X",
        "position": 0,
        "stddev": 12.64424578,
        "variance": 159.8769514
      },
      {
        "average": -1.399266328,
        "count": 53773852,
        "maximum": 22.56153297,
        "minimum": -60.2872963,
        "name": "Y",
        "position": 1,
        "stddev": 6.769987871,
        "variance": 45.83273577
      },
      {
        "average": 2.607783115,
        "count": 53773852,
        "maximum": 23.07263947,
        "minimum": -5.98761034,
        "name": "Z",
        "position": 2,
        "stddev": 1.404187613,
        "variance": 1.971742852
      },
      {
        "average": 65535,
        "count": 53773852,
        "maximum": 65535,
        "minimum": 65535,
        "name": "Intensity",
        "position": 3,
        "stddev": 8.936917196,
        "variance": 79.86848896
      },
      {
        "average": 1,
        "count": 53773852,
        "maximum": 1,
        "minimum": 1,
        "name": "ReturnNumber",
        "position": 4,
        "stddev": 0.0001363686152,
        "variance": 1.859639921e-08
      },
      {
        "average": 1,
        "count": 53773852,
        "maximum": 1,
        "minimum": 1,
        "name": "NumberOfReturns",
        "position": 5,
        "stddev": 0.0001363686152,
        "variance": 1.859639921e-08
      },
      {
        "average": 0,
        "count": 53773852,
        "maximum": 0,
        "minimum": 0,
        "name": "ScanDirectionFlag",
        "position": 6,
        "stddev": 0,
        "variance": 0
      },
      {
        "average": 0,
        "count": 53773852,
        "maximum": 0,
        "minimum": 0,
        "name": "EdgeOfFlightLine",
        "position": 7,
        "stddev": 0,
        "variance": 0
      },
      {
        "average": 32,
        "count": 53773852,
        "maximum": 32,
        "minimum": 32,
        "name": "Classification",
        "position": 8,
        "stddev": 0.004363795686,
        "variance": 1.904271279e-05
      },
      {
        "average": 0,
        "count": 53773852,
        "maximum": 0,
        "minimum": 0,
        "name": "ScanAngleRank",
        "position": 9,
        "stddev": 0,
        "variance": 0
      },
      {
        "average": 0,
        "count": 53773852,
        "maximum": 0,
        "minimum": 0,
        "name": "UserData",
        "position": 10,
        "stddev": 0,
        "variance": 0
      },
      {
        "average": 0,
        "count": 53773852,
        "maximum": 0,
        "minimum": 0,
        "name": "PointSourceId",
        "position": 11,
        "stddev": 0,
        "variance": 0
      },
      {
        "average": 46461.03622,
        "count": 53773852,
        "maximum": 61680,
        "minimum": 15420,
        "name": "Red",
        "position": 12,
        "stddev": 11407.8311,
        "variance": 130138610.4
      },
      {
        "average": 48540.29937,
        "count": 53773852,
        "maximum": 61680,
        "minimum": 15420,
        "name": "Green",
        "position": 13,
        "stddev": 10192.46728,
        "variance": 103886389.2
      },
      {
        "average": 49397.45554,
        "count": 53773852,
        "maximum": 61680,
        "minimum": 15420,
        "name": "Blue",
        "position": 14,
        "stddev": 10971.27374,
        "variance": 120368847.5
      }
    ]
  }
}

[hobu]

This data is silly.

[hobu]

QGIS should warn and clamp data it sees with scale < 1e-6. This isn't Untwine's bug to fix. We can't decide to clamp the data for the user.

Note: The file in question here is in the last two items of this useful XKCD primer on geographic coordinate precision.

[abellgithub]

@wonder-sk : I think this should be as resolved as possible thanks to #149.

[uclaros]

Indeed, the file now gets indexed successfully, you can close this.