1. Introduction

Las to Las registration is a tool available in LP360 Land starting from v2023.2. The module can be found on the Tools ribbon section. LAS to LAS registration requires "LP360 Land Standard" license or the "LP360 Land Standard" addon.

Manual registration is a tool performing coarse alignment, in other words it performs a rigid registration where the user manually aligns multiple LAS.

If you are looking for other types of registration, please check the article on LAS to Control registration or LAS to LAS Auto registration.

2. How to use LAS to LAS registration

Before using LAS to LAS manual registration, make sure to have at least 2 point clouds, and identify each point cloud. One will be used as a referenced and the other will be registered.

1. Open LAS to LAS Manual Registration tool.
2. Select the "Reference LAS Layer"
3. Select the "Registered LAS Layer"
4. Press "Pick A New Pair"

5. Select one pair of common point in both point clouds
6. Measure a common point in the "Registered" point cloud.
7. Measure a common point in the "Reference" point cloud.
8. Press "Validate The Picked Pair"

9. Repeat the process until you have multiple pairs measured
10. Select the registration correction type:
- Translation: always recommended.
- Rotation: recommended if you can identify multiple pairs of points spread around the point cloud.
- Scale: only for advance users. It can deform the 3D model if not applied properly.
11. Press "Solve", the tool will calculate the values to be applied to the registration
12. Review the registration values.
Note: If a pair of points is not accurate enough the tool will warm the user
13. Press "Apply Corrections"

14. A new registered point cloud will be created in the table of content

3. Good practices

- Use at least 3 pairs of common points for translation (minimum required is 1).
- Use at least 6 pairs of common points for rotation (minimum required is 3).
- Spread the measurement pairs across the point cloud, avoid measuring all the pairs of points next to each other.
- In case of having multiple point clouds to register, use the most confidence point cloud as reference. For example:

a) Multiple SLAM point clouds. Use the point cloud that overlap with more point cloud as a reference.
b) SLAM and RTK/PPK. Use the georeferenced point cloud from RTK/PPK as a reference.
c) Drone mapping and SLAM. Use the georeferenced point cloud from drone mapping as a reference.
d) Drone mapping and RTK/PPK. Use the georeferenced point cloud from drone mapping as a reference.