Reprojecting Point Clouds FAQs

This FAQ covers how Aura handles reprojection during point cloud processing, including the dual trajectory output, colorization of reprojected data, 360 image extraction, and reprojection of legacy datasets.

Frequently asked questions

Why are there two trajectories in the Output folder when reprojecting as part of the processing workflow?

Two trajectories are provided in the output for different purposes.

SLAM projection trajectory:

Required for accurate colorization. It is automatically selected when colorizing a reprojected dataset.
The colorized output maintains the target CRS that was applied to the selected SLAM output folder during colorization.

Target projection trajectory (with _projected suffix):

Used for viewing the trajectory alongside the reprojected point cloud in the same CRS.
Used for extracting 360 images, which are also reprojected to the target CRS.

How can I colorize a reprojected point cloud?

Process the RTK dataset with reprojection before colorizing it as usual. The colorization process uses the default SLAM projection trajectory to ensure accurate results. The point cloud output after colorization is in the target projection.

How do I extract 360 images from a reprojected point cloud?

To use 360 Image Extract, the trajectory in the Output folder must use the default naming convention (for example, scan_folder_name_traj.xyz).

To use a reprojected trajectory, rename both the reprojected and the original TRAJ and PRJ files in the Output folder so that the reprojected files adopt the default naming convention.

Step 1: Rename the reprojected files

Reprojected filename	Rename to
`scan_folder_name_traj_projected.xyz`	`scan_folder_name_traj.xyz`
`scan_folder_name_traj_projected.prj`	`scan_folder_name_traj.prj`

Step 2: Rename the original files

Original filename	Rename to
`scan_folder_name_traj.xyz`	`scan_folder_name_traj_nonreprojected.xyz`
`scan_folder_name_traj.prj`	`scan_folder_name_traj_nonreprojected.prj`

Once the filenames have been renamed, run 360 Image Extract as normal.

My point cloud was reprojected into a target horizontal CRS using an earlier version of Aura (1.7 or earlier). Can I reproject it into a target vertical CRS to apply a GEOID?

Yes. Load the point cloud or trajectory in Aura, then:

Select Export reprojection from the Projects menu.
Keep the source horizontal CRS as is and leave the vertical CRS blank.
Use the source horizontal CRS as the target CRS and specify a vertical CRS to apply the GEOID.