Affine Transform LAS Point Cloud Task

The Affine Transform LAS Point Cloud Task (PCT) is a powerful tool designed to modify the coordinates of LAS point cloud data. It is commonly used for:

• Grid-to-ground conversions
• Local site calibrations
• Debiasing
• Applying horizontal rotation, scale, and translation

This task supports both component-based transformations (Rotate, Scale, Translate) and direct matrix input, making it flexible for a wide range of geospatial workflows.

Parameters

Figure 1: Affine Transform LAS Parameters dialog

Input Datasets

Select the data to which to apply the affine transform.

• • Feature Geometry - Defines the area to apply the affine transform.
  • Input LAS Layer - Select the points within the dataset to use in the processing.
    • • Input Points Filter - Opens the Live View to allow filtering of which points to use from the input LAS Layer.

Transformation Settings

Figure 2: Rotate, Scale, Translate and Origin settings

• Rotate: Specify rotation angles (typically in degrees) around the X, Y, or Z axis.
  • Select the order the axis of rotation, "X,Y,Z" or "Z, Y, X". The latter is the default.
• Scale: Enter scale factors for each axis.
• Translate: Input translation values to shift the point cloud.
• Origin: Define the origin point for rotation and scaling operations.

Matrix Settings

• If you prefer matrix math, input the 3x3 transformation matrix and translation vector directly.
• LP360 will auto-calculate the matrix from component inputs if both are used.

Output Settings

• Output Folder: Select an output location to write the transformed LAS dataset.
• Output Layer Name: Introduced in 2025.2, the user may specify the name for the corrected LAS Layer, for example, "Debiased LAS" or "Local LAS", in place of the default name, "<Default>", where the legacy auto-naming convention is used, "LAS_Layer#".
• Maintain Source File Structure: Keeps the original tiling of LAS files. Each output file maps one-to-one with its source.
• GeoTag as Local SRS: Tags the output LAS files with a local Spatial Reference System (SRS) aka local Coordinate Reference System (CRS), including the units (e.g., survey feet, meters), indicating they are in a non-standard or arbitrary Local Coordinate System (LCS).

Workflow: Applying Affine Transform LAS PCT

1. Create the Task:
   • In LP360, go to the Point Cloud Task Manager .
   • Add a new task and select Affine Transform LAS as the type.
2. Configure Parameters:
   • Input Rotate, Scale, Translate values or use matrix input.
   • Set the origin if needed.
3. Run the Task:
   • Execute the task using the Point Task tab.
   • Verify the output using visual inspection or control points.
4. Export the Task:
   • Save the task as an XML file for reuse or batch processing.
   • Ensure only the Affine Transform PCT is selected during export.

📎 Tips & Resources

• Use TerraScan for deriving transformation values from control point pairings.