filters.ferry.rst

filters.ferry

The ferry filter copies data from one dimension to another, creates new dimensions or both.

The filter is guided by a list of 'from' and 'to' dimensions in the format <from>=><to>. Data from the 'from' dimension is copied to the 'to' dimension. The 'from' dimension must exist. The 'to' dimension can be pre-existing or will be created by the ferry filter.

Alternatively, the format =><to> can be used to create a new dimension without copying data from any source. The values of the 'to' dimension are default initialized.

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Example 1

In this scenario, we are making copies of the X and Y dimensions into the dimensions StatePlaneX and StatePlaneY. Since the reprojection filter will modify the dimensions X and Y, this allows us to maintain both the pre-reprojection values and the post-reprojection values.

{
  "pipeline":[
    "uncompressed.las",
    {
      "type":"readers.las",
      "spatialreference":"EPSG:2993",
      "filename":"../las/1.2-with-color.las"
    },
    {
      "type":"filters.ferry",
      "dimensions":"X => StatePlaneX, Y=>StatePlaneY"
    },
    {
      "type":"filters.reprojection",
      "out_srs":"EPSG:4326+4326"
    },
    {
      "type":"writers.las",
      "scale_x":"0.0000001",
      "scale_y":"0.0000001",
      "filename":"colorized.las"
    }
  ]
}

Example 2

The ferry filter is being used to add a dimension 'Classification' to points so that the value can be set to '2' and written as a LAS file.

{
  "pipeline":[
    {
        "type": "readers.gdal",
        "filename": "somefile.tif"
    },
    {
        "type": "filters.ferry",
        "dimensions": "=>Classification"
    },
    {
        "type": "filters.assign",
        "assignment": "Classification[:]=2"
    },
    "out.las"
  ]
}

Options

dimensions

A list of dimensions whose values should be copied. The format of the option is <from>=><to>, <from>=><to>,... Spaces are ignored. 'from' can be left empty, in which case the 'to' dimension is created and default-initialized. 'to' dimensions will be created if necessary.

Note: the old syntax that used '=' instead of '=>' between dimension names is still supported.