DJI Terra Pre-processing for the L1/L2 Processed workflow

DJI Terra is a software developed by DJI and it is used as part of the DJI L1/L2 Processed workflow.

This article explains the main steps to perform in DJI Terra before importing the data into LP360 Drone to continue with the workflow. This software will perform the trajectory processing step and the initial point cloud generation.

The information in this article may not be up to date with the latest changes in DJI Terra, and it is meant to be used as guidance on how to use the software. This guide was created using DJI Terra v4.3.0.

Use the official DJI channels to learn more about how to use DJI Terra software.

How to pre-process a DJI L1/L2 dataset in DJI Terra

1. Open DJI Terra
2. Go to the flight route section --> Press New Mission
3. In mission Type --> Select "LIDAR Point Cloud"
4. Give a name to the processing
5. In the "Files" section--> Press "Select Folder" and select the raw data folders to process
6. If processing in RTK you can continue to step 7.
If processing with PPK -->Press in "Base Station Center Point Settings" --> Input the coordinates of the base station.
  Note: before processing PPK in DJI Terra, it is recommended to use the DJI PPK Utility in LP360 to properly import the base station file in RINEX format.

7. Parameters section:
a) Scenario -->Point Cloud Processing
b) Point Cloud 
          i) By Percentage-->High(100%) 
          ii) Point Cloud Effective Distance Range --> 3m - 300m
          iii) Optimize Point Cloud Accuracy --> Disabled
          iv) Smooth Point Cloud -->Disabled

c) Ground Point Classification, DEM, Contour --> Disabled

d) Advanced Control and Check --> Known Coordinate System --> Select a known coordinate system. The recommendations are:
        i) Global: Select the CRS with the datum matching, as your base station or RTK corrections datums. For example: If your base station coordinates introduced in the DJI PPK Utility are in NAD83(2011), select as LAS CRS NAD83(2011).

Other possible CRS:
        ii) Global: WGS84 / UTM zone XX  + Geoid: default
        iii) North America: NAD83 (2011) / State Plane zone XX + Geoid: default
        iiii) Europe: ETRS89 / UTM zone XX + Geoid: default

Note: Geoid default means ellipsoidal height
Note 2: LP360 will reproject the data from DJI Terra, however, it needs to know the exact CRS selected in DJI Terra. For North America, we recommend using NAD83(2011) with the State Plane projection, however, if the user does not find a proper CRS with the EPSG code and correct units, it is possible to use a different projection for example, NAD83(2011) UTM in meters.

Note: During the Processing in LP360, LP360 will ask for the output CRS selected in DJI Terra. The LAS CRS is the one selected in DJI Terra, the SBET CRS is the horizontal datum with ellipsoidal height in meters, without projection. Horizontal datums example, WGS84 + ellipsoidal, NAD83(2011) + ellipsoidal or ETRS89 + ellipsoidal.

8. Press "Start Processing" --> Wait until the processing is done
9. Close DJI Terra software
10. Go to the default DJI Terra folder --> Find the DJI Terra Mission Folder for the project. This folder will be required during the processing in LP360.

Note: If you move the Raw data or the DJI Terra Mission Folder, LP360 will ask for the new location of these folders.
Note 2: Only AT and lidars folders are required by LP360. Inside lidars folder, you can exclude terra_pnts folder.

11. Continue the DJI L1/L2 Processed workflow in LP360 Drone