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.

Before working in Terra, prep your data. Transfer the LiDAR mission from the L2 microSD card to your computer. Download your check shots and 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.

Step-by-Step Point Cloud Processing

In DJI Terra, start a new LiDAR point cloud mission, click the folder icon, and navigate to the mission folder you have prepped.

Click the Base Station Center Point Settings. Input your base coordinate that you processed in OPUS and add your antenna height (pole height + antenna offset), and Save.

In the LiDAR Point Cloud dropdown, you can fine-tune how you’d like to process your data, including Point Cloud Density, smoothing, ground point classification, or generating a DEM. In the Advanced section, you can select your Coordinate System and the processing format for your point cloud.

Annotations, Ground Checks, and Calibration

In the Applications dropdown, you can access your Annotation and Measurement tools.

Back in the Advanced section, you can add Ground Check and Ground Control points. Import a CSV of your Check Shots. Classify your columns to identify your Check Shot coordinates. Importing the points as Ground Control points 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.

Start Processing after double-checking your parameters and clicking OK. You will be 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 provide information about the entirety of the mission including a comparison of the elevation distance from the L2 data vs the Check Points.

Utilizing Built-in Measurement Tools

Access the measurement tools inside the software interface to query your data directly:

• The Coordinate tool: Lets you select a point and check the coordinates. You can also Name and Save the point.
• The Distance tool: Lets you select points and find the distance between them. You can Name and Save the line.
• The Area and Volume tools: Let you measure the area and volume in the point cloud respectively.

Exporting and Downstream CAD Workflows

To export the point cloud, select the Home icon and click the export button below your mission.

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.