DJI Zenmuse L2 PPK Workflow

This guide covers processing a DJI Zenmuse L2 LiDAR point cloud in DJI Terra, some of the tools available for measurements and annotations, and exporting your point cloud file. All of the software and tools demonstrated are available for DJI Zenmuse L2 LiDAR data without a subscription for Terra.

In this article, we will show you how to process your DJI Zenmuse L2 LiDAR data and some of the free tools Terra has to offer. Before we begin in Terra, we are going to do a little prep with our data. First you must transfer the LiDAR mission from the L2 SD card, download your check shots, and download your observation file from your Emlid Reach base. Move the observation file(.24O) from your base to the mission folder and change the file extension of your observation file to OBS.

In Terra, start a new LiDAR point cloud mission. Select the folder icon in the top right and import your mission folder. Click on the “Base Station Center Point Settings” and input your base’s coordinates that you processed in OPUS and add your antenna height (pole height + antenna offset). Click Save.  

In the LiDAR Point Cloud dropdown, you can fine tune how you would like to process your data. First is Point Cloud Density where you can enable smoothing, ground point classification, or generate a DEM. In the Advanced section you can select your Coordinate System and the processing format for your point cloud. You can also add Ground check and Ground Control Points. In the Applications dropdown, you can access your Annotation and Measurement tools.  

In the Advanced section, click the arrow icon and then the magnifying glass icon to import a CSV of your Check Shots. Classify your Data Columns to identify your Check Shot coordinates. Click Import. These will be imported as Ground Control Points which will affect your point cloud elevation by pulling the point cloud to those elevations at those coordinates. Selecting Check Point in the Type dropdown will only compare the points to the point cloud and give you an accuracy check. Back out and Click Start Processing. Review your Parameters Checklist for any errors, then Click OK.  

After processing, you are presented with your Point Cloud. You can toggle through filters to see the data as RGB, Reflectivity, or Height. You can also view a Quality Report within Terra that will give you information about the entirety of the mission including a comparison of the elevation distance from the L2 data vs the Check Points.

The last thing we will look at before exporting our point cloud will be the Annotation and Measurement tools. The Coordinate tool lets you select a point and check its coordinates. You can Name and Save that point as well. The Measurement tool will let you select points and find the distance between them. You can name and save that line as well. The Area and Volume tools let you measure an area or volume respectively.  

Finally to export your point cloud, Click on the Home icon in the top left. Click on your mission and then the export button.

You can now import the DJI Terra point cloud into other processing software such as BricsCAD to do further work with the data. The Zenmuse L2 provides LiDAR drones with more precise, efficient, and reliable geospatial data acquisition especially when paired with the Emlid Reach receivers.