writers.ept_addon

The EPT Addon Writer supports writing additional dimensions to Entwine Point Tile datasets. The EPT addon writer may only be used in a pipeline with an EPT reader, and it creates additional attributes for an existing dataset rather than creating a brand new one.

The addon dimensions created by this writer are stored independently from the corresponding EPT dataset, therefore write-access to the EPT resource itself is not required to create and use addon dimensions.

Default Embedded Stage

This stage is enabled by default

Example

This example downloads the Autzen dataset (10M points) and runs the :ref:`filters.smrf <SMRF filter>`_, which populates the Classification dimension with ground values, and writes the resulting attribute to an EPT addon dataset on the local filesystem.

[{
   "type": "readers.ept",
   "filename": "http://na.entwine.io/autzen/ept.json"
}, {
   "type": "filters.assign",
   "assignment": "Classification[:]=0"
}, {
   "type": "filters.smrf"
}, {
   "type": "writers.ept_addon",
   "addons": { "~/entwine/addons/autzen/smrf": "Classification" }
}]

And here is a follow-up example of reading this dataset with the :ref:`readers.ept <EPT reader>`_ - with the created addon overwriting the Classification value - and then writing the output to a single file with the :ref:`writers.las <LAS writer>`_.

[{
   "type": "readers.ept",
   "filename": "http://na.entwine.io/autzen/ept.json",
   "addons": { "Classification": "~/entwine/addons/autzen/smrf" }
}, {
   "type": "writers.las",
   "filename": "autzen-ept-smrf.las"
}]

Here is an example of using multiple mappings in the addons option, to apply a new color scheme with filters.colorinterp mapping the Red, Green, and Blue dimensions to new values.

[{
   "type": "readers.ept",
   "filename": "http://na.entwine.io/autzen/ept.json"
}, {
   "type": "filters.colorinterp"
}, {
   "type": "writers.ept_addon",
   "addons": {
      "~/entwine/addons/autzen/interp/Red":   "Red",
      "~/entwine/addons/autzen/interp/Green": "Green",
      "~/entwine/addons/autzen/interp/Blue":  "Blue"
   }
}]

And to read the data with the new colors:

[{
   "type": "readers.ept",
   "filename": "http://na.entwine.io/autzen/ept.json",
   "addons": {
      "Red":   "~/entwine/addons/autzen/interp/Red",
      "Green": "~/entwine/addons/autzen/interp/Green",
      "Blue":  "~/entwine/addons/autzen/interp/Blue"
   }
}, {
   "type": "writers.las",
   "filename": "autzen-ept-interp.las"
}]

Options

addons
A JSON object whose keys represent output paths for each addon dimension, and whose corresponding values represent the attributes to be written to these addon dimensions. [Required]

Note

The addons option is reversed between the EPT reader and addon-writer: in each case, the right-hand side represents an assignment to the left-hand side. In the writer, the dimension value is assigned to an addon path. In the reader, the addon path is assigned to a dimension.

threads
Number of worker threads used to write EPT addon data. A minimum of 4 will be used no matter what value is specified.