Start by creating a dedicated Merge subdirectory in the SLAM session (at this stage, you are supposed to be in ./slam_session_tutorial/2_georef . If you are not, please catch-up by doing the previous tutorial 5. Georeference a SLAM session)

mkdir ../3_merge
cd ../3_merge

The exwayz_merge_cloud.exe executable expects

A directory containing frames such as the one created by exwayz_slam.exe .
A support trajectory on which the frames will be accumulated. This trajectory could be the odometry trajectory from exwayz_slam.exe , the loop closure trajectory from exwayz_loop_closure.exe or the GNSS fusion trajectory from exwayz_georef.exe .

To merge the point cloud, run the following commands

exwayz_merge_cloud -i ../frames -t ../2_georef/traj_fusion_gps.ply \\
-d 0.1 --r-min 3.0 -o ./merged.laz --split 30

Optional parameters

`-d`	This is the merge update distance : it prevents from aggregating frames that are too close by allowing the accumulating only between frames spaced by at least `-d` meters.
`--r-min`	Discards, in each frame, all points with a range lesser than `--r-min`. It is useful to remove points that appear on each frame consistently such as points belonging to the sensor’s mounting platform.
`-o`	Name of the output file. Note that specifying the extension in the name will define in which format the point cloud will be written (default is `.ply`, but it can be `.las` or `.laz`).
`--split`	Allows the software to split the merged point cloud into chunks of ~`--split` millions of points. This option helps preventing exceeding the total RAM capacity of the computer during the merging step.

The final SLAM session directory should be structured as follow

📂 slam_session_<hour>_<date>

📂 1_loop_closure
📂 2_georef
📂 3_merge
📂 frames

traj_odometry.ply ****# Odometry trajectory computed by the SLAM

traj_odometry_sync.ply # Odometry trajectory synched with the GPS trajectory, if resynchronization option was turned on

traj_gps.ply ****# Eventual GPS trajectory in Exwayz format

Want to go further?

The previous tutorial aimed at getting you on track quickly on a sample dataset. There is an advanced usage of Exwayz software that will allow you to refine each step, and to use more “expert” features such as the multi-session SLAM or the map cleaning.

Don’t hesitate to check the advanced tutorials and the developer’s documentation for more information!

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FAQ

Is there a way to remove the points belonging to the platform of my vehicle automatically?