Optimizing Data from Multiple Scans

LiDARSnap trajectory optimization can be used to merge multiple scans from multiple trajectories into one CLOUD file. A single CLOUD file can be built from multiple sets of raw data (multiple PLP files, each with associated lidar and trajectory data). However, relative accuracy between the individual scans may be poor, due to vertical drift or other trajectory errors, so running LiDARSnap trajectory optimization is recommended. An example below illustrates this process with two aerial data sets.

Before combining multiple projects, process all of your trajectories independently using NavLab via LiDARMill, NavLab embedded, or InertialExplorer.

To begin multi-mission processing, open all PLP files. You should then see that you have several sets of trajectories. In the example below, three projects are being processed together:

Three project files opened in SpatialExplorer

Note that you have multiple PLP files open. At this point it's recommended to save this multi-PLP project as a new file so that you can easily re-open the group project again:

Flights 1 through 3 are saved to a master project, containing all flights' data

Create Intervals. Intervals will be created from both mission's trajectories:

Create a point cloud using the flightline intervals from both missions:

Next, to resolve any differences between trajectories, run LiDARSnap. In this example, we will use the Aerial Trajectory Optimization preset:

Upon completion of LiDARSnap, a new optimized trajectory for each mission is created and loaded into the project window under Trajectories:

The point cloud will be automatically recomputed in respect to these new, optimized trajectories. Note that the cloud now has unsaved changes, indicated by the asterisk and italicized font, as the cloud has been recomputed to the new, optimized trajectories:

If you are satisfied with the LiDARSnap results, File->Save the project to make the changes to the cloud permanent.