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readers.ept

Entwine Point Tile (EPT) is a hierarchical octree-based point cloud format suitable for real-time rendering and lossless archival. Entwine is a producer of this format. The EPT Reader supports reading data from the EPT format, including spatially accelerated queries and file reconstruction queries.

Sample EPT datasets of hundreds of billions of points in size may be viewed with Potree or Plasio.

.. embed::

Example

This example downloads a small area around the the Statue of Liberty from the New York City data set (4.7 billion points) which can be viewed in its entirety in Potree or Plasio.

[
   {
      "type": "readers.ept",
      "filename": "http://na.entwine.io/nyc/ept.json",
      "bounds": "([-8242669, -8242529], [4966549, 4966674])"
   },
   "statue-of-liberty.las"
]

Additional attributes created by the :ref:`EPT addon writer <writers.ept_addon>` can be referenced with the addon option. Here is an example that overrides the Classification dimension with an addon dimension derived from the original dataset:

[
    {
        "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"
    }
]

For more details about addon dimensions and how to produce them, see :ref:`writers.ept_addon`.

Options

filename
EPT resource from which to read. Because EPT resources do not have a file extension, to specify an EPT resource as a string, it must be prefixed with ept://. For example, pdal translate ept://http://na.entwine.io/autzen autzen.laz. [Required]
spatialreference
Spatial reference to apply to the data. Overrides any SRS in the input itself. Can be specified as a WKT, proj.4 or EPSG string. [Default: none]
bounds
The extents of the resource to select in 2 or 3 dimensions, expressed as a string, e.g.: ([xmin, xmax], [ymin, ymax], [zmin, zmax]). If omitted, the entire dataset will be selected.
resolution

A point resolution limit to select, expressed as a grid cell edge length. Units correspond to resource coordinate system units. For example, for a coordinate system expressed in meters, a resolution value of 0.1 will select points up to a ground resolution of 100 points per square meter.

The resulting resolution may not be exactly this value: the minimum possible resolution that is at least as precise as the requested resolution will be selected. Therefore the result may be a bit more precise than requested.

addons

A mapping of assignments of the form DimensionName: AddonPath, which assigns dimensions from the specified paths to the named dimensions. These addon dimensions are created by the :ref:`EPT addon writer <writers.ept_addon>`. If the dimension names already exist in the EPT Schema for the given resource, then their values will be overwritten with those from the appropriate addon.

Addons may used to override well-known :ref:`dimension <dimensions>`. For example, an addon assignment of "Classification": "~/addons/autzen/MyGroundDimension/" will override an existing EPT Classification dimension with the custom dimension.

origin

EPT datasets are lossless aggregations of potentially multiple source files. The origin options can be used to select all points from a single source file. This option may be specified as a string or an integral ID.

The string form of this option selects a source file by its original file path. This may be a substring instead of the entire path, but the string must uniquely select only one source file (via substring search). For example, for an EPT dataset created from source files one.las, two.las, and two.bpf, "one" is a sufficient selector, but "two" is not.

The integral form of this option selects a source file by its OriginId dimension, which can be determined from the file's position in EPT metadata file entwine-files.json.

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