Dataset Parameters
Minimum Voxel Length
An EPT dataset is divided up into different depths, where each depth captures increasingly more detail. At each depth, the volume of the point cloud is divided up into voxels. Each subsequent depth level bisects the volume of the previous depth level, thus halving the length of each voxel.
This parameter selects a subset of depths to read by specifying a minimum length in ground units for each voxel. All depths that have a voxel length greater than or equal to the specified length will be included in the point cloud.
For example, suppose we have an EPT dataset with the following properties:
Depth 0: 8 meters / voxel
Depth 1: 4 meters / voxel
Depth 2: 2 meters / voxel
If this parameter is set to 3, then depths 0 and 1 will be read.
If this parameter is set to 1, then depths 0, 1, and 2 will all be read.
Note: Depth 0 will always be read, even if this parameter specifies a value greater than the depth 0 voxel length.
If this parameter is not specified, all depths will be read.
Addon Components
Addons are datasets containing additional components that can be added to an existing EPT dataset in order to add or change values, without rewriting the entire dataset. These can be created by the Point Data Abstraction Library (PDAL).
This parameter specifies the addon components to read, and the corresponding ept-addon.json datasets for those components. Note that the reader dataset is an ept.json file, and each addon component dataset is a separate ept-addon.json file. These are not interchangeable (that is, a reader dataset can't be used as an addon dataset, and an addon dataset can't be used as a reader dataset). Each addon component dataset resides in a separate folder, and each ept-addon.json file must be explicitly selected. For example:
Use Search Envelope
Using the minimum and maximum x and y parameters, define a bounding box that will be used to filter the input features. Only features that intersect with the bounding box are returned.
If all four coordinates of the search envelope are specified as 0, the search envelope will be disabled.
Clip to Search Envelope
When selected, this parameter removes any portions of imported features being read that are outside the Search Envelope.
The example below illustrates the results of the Search Envelope when Clip to Search Envelope is not selected (set to No) and when it is selected (set to Yes).
- No: Any features that cross the search envelope boundary will be read, including the portion that lies outside of the boundary.
- Yes: Any features that cross the search envelope boundary will be clipped at the boundary, and only the portion that lies inside the boundary will be read. The underlying function for the Clip to Search Envelope function is an intersection; however, when Clip to Search Envelope is selected, a clipping operation is also performed in addition to the intersection.
Schema Attributes
Additional Attributes to Expose
Use this parameter to expose Format Attributes in Workbench when you create a workspace:
- In a dynamic scenario, it means these attributes can be passed to the output dataset at runtime.
- In a non-dynamic scenario, this parameter allows you to expose additional attributes on multiple feature types. Click the browse button to view the available format attributes (which are different for each format) for the reader.