Requires an LP360 Land Standard, a BIT add-on for LP360 Drone, or an LP360 Geospatial Advanced license.

The LAS to Control Manual Registration on the Tools Tab and TVGO Tab of the ribbon is used to perform coarse alignment of a point cloud to control. In other words, it performs a rigid registration where the user manually aligns a LAS to Control Points. The LAS to Control Manual Registration tool is also useful for computing Translation, Scale, and/or Rotation to transform a point cloud to a local coordinate system, sometimes also known as an arbitrary coordinate system. When the values are already known, use the Affine Transform LAS Point Cloud Task to apply them instead.  

Figure 1: LAS to Control Manual Registration in the Tools Tab

For other types of registration, please see LAS to LAS Auto Registration or LAS to LAS Manual Registration .

Figure 2: LAS to Control Manual Registration dialog

Input

Registered LAS Layer: The LAS Layer to be registered to the control found on the Feature Layer. 

Feature Layer: The Feature Layer to be used as the reference layer. Points in this layer are not written to the output.

Pairs

Pick The Corresponding Point

After selecting a control point in the grid, press Pick The Corresponding Point to manually measure the location of the control point in the point cloud. 

Validate The Picked Point

After measuring the control point location, validate the picked point by pressing the Validate The Picked Point to validate the point picked from the point cloud.

Results

Correction: The origin, translation, rotation, and scale values of the derived rigid correction. Populated by executing Solve.

RMSE: Describes how well the point cloud aligns to the control. The "After" value should be smaller than the "Before" value to see any improvement in the alignment. Populated by executing Solve.

Options

Select the registration correction type:

• Translation: Always recommended.
• Rotation: Recommended if you can identify multiple pairs of points spread throughout the point cloud.
• Scale: For advance users as it can deform the 3D model if not applied correctly and is not typically needed when registering TrueView GO data.

Commands

Help to open this help page.

Solve will calculate the values to be applied to register the "Registered LAS Layer" to the "Feature Layer" and display the before and after RMSE values. Enable the Auto Solve checkbox to automatically recalculate the values as you make changes to the point pairs. 

Apply Corrections to create the output layer which will contain the corrected points from "Registered LAS Layer" and have the naming convention, NameofRegisteredLASLayer_Registered_YYMMDD_hhmmss, where the date and timestamp in the name correspond to when the Apply Corrections was executed.

Cancel to close the tool without applying corrections.

How to use LAS to Control Manual Registration

Before using LAS to Control manual registration, make sure that the control points are visible in the LAS. Translation requires a minimum of one Control Point. Rotation requires a minimum of three Control Points. It is recommended to perform Translation and Rotation.

1. Use the Import Control tool from the Control Points Tab to import new control from a text file, or the Add Files -> Feature tab to add an existing control point feature file.
2. Select the LAS to Control Manual Registration tool.
3. Select the LAS Layer you would like to register as the "Registered LAS Layer".
4. Select the imported control points as the "Features layer".
5. Select a control point from the list.
6. Press "Pick The Corresponding Point".

Figure 3: Pick the corresponding point in the point cloud

7. Measure the point in the point cloud.
8. Press "Validate The Picked Point".

Figure 4: Validate the point picked from the point cloud

9. Repeat the process until you have multiple points measured.
10. Select the applicable registration correction types.
11. Press "Solve", to calculate the correction values to be applied.
12. Review the values computed as the correction. Note: If a point is not accurate enough the tool will warn the user.
13. Press "Apply Corrections" to apply the corrections to the "registered LAS Layer" and generate a new registered point cloud in the Table of Contents (TOC).

Figure 5: Compute and apply the correction

Figure 6: The registered point cloud

Good Practices

• Use at least three pairs of common points for translation (One is the minimum required).
• Use at least six pairs of common points for rotation (Three is the minimum required).
• Spread the control points across the point cloud so they are well distributed.
• Remember that the accuracy of the control points will affect the overall accuracy of the registered LAS.