DJI Mini 2 SE/4K Mapping Tutorial

 DJI Mini 2 SE /4K Mapping Tutorial

Low cost drone mapping approach

DJI no longer provides SDK tools with their lower cost general purpose drones like the DJI mini series. This means that users will have to use the DJI Fly application to control their drones. Android and iOS apps like Litchi, DroneLink, Map Pilot Pro, etc. cannot directly control the low cost DJI drones like the mini 4K with their apps. 

This makes mapping with their low end drones more difficult. However it is still possible with some work arounds. You can use your DJI drone for mapping by followint the YouTube's "Turn your DJI Drone into a mapping machine for free!" video tutorial by Dylan Gorman. You will need to create a default kmz file on the DJI Fly app and manually overwrite that with your mapping kmz file created with the Map Pilot Pro (Maps Made Easy) app of the mission you want to complete. Note: the limitation also holds for this approach because DJI does not work with the kmz files for their low end drones. We will investigate this further.

DJI Fly Application

You need to learn how to use the DJI Fly application to fly your DJI mini drone and to set up the default kmz file so that you can upload future kmz mapping missions for the mini drone to run. See some of the YouTube links below under Video Tutorials.

Litchi for DJI Drones

After some additional research we discovered that the DJI mini 2  and 2 SE is supported by the Litchi for DJI Drones app although their website Litchi.com does not include the DJI mini 2 as a supported product, however DJI has provided the SDK for the mini 2 that allows the app to work with the drone, consequently we can use a work around to generate 2D maps with the drone.


Steps to create a 2D Map

1. Install the app on your mobile phone (we are using an Android device).
2. Follow the User Guide to connect the Litchi app on your phone via the controller to the drone. 
3. Use your computer or tablet to access the Litchi website and select the Mission Hub tab to create your mission waypoint kmz file and save the file in Litchi's cloud server.
4. Head out to your project site and connect your drone to your phone with the Litchi app and load the mission file you saved.
5. Launch your mission.
6. Download the 2D photos from the flight to process into a 2D map.

Note: we discovered that the photos taken with the app does not have elevation data that are needed for some of the online mapping sites. Consequently we used an app that knitted the photos together to create a base map image. 

Kolor Autopano Giga v4.4

We found a reference to a pretty good pano stitcher which has been abandoned by its developers back in 2018 which could be used to stitch the DJI 2D photos together to make a map. The following url from the mavicpilots forum will provide details for the download and installation of the app.


Tutorial Using Litchi Mission Hub

Step 1 - Litchi Website Launch Mission Hub

On the Litchi website select the Mission tab option to create your mission waypoint file. Use your mouse to move to the location of your project. Litchi Mission uses Google Earth type basemap you can move, zoom in and out to your selected project geo-location.

Step 2 - Create Flight Waypoints

Select your first start waypoint and enter the drone flight parameters in the waypoint popup form. An example is shown in the figure below.
 

Enter the Altitude (m) value of 80 m above the 'starting elevation' of the drone. Note: you can set the drone to follow the ground by activating the Above Ground button, but you do not want that for photogrammetry. You want the drone to fly in a fixed plane above the ground, however you need to make sure that the Altitude selected will be clear of any ground obstacles. 

In our example Speed (m/s) is set at 5 m/s. We have set the Heading of the drone to follow the flight lines. You can do that by moving the slider button while looking at the direction arrow on the waypoint on the screen in Mission Hub.

The next parameter to set is the gimbal Angle (degrees). It is set at -90 degrees to point the camera on the gimbal to the ground. Zero degrees is the horizontal setting for the camera. The Interval is the time between each picture frame and it is set to 3.0 seconds.

These values are set for each waypoint on the mission plan.

Step 3 - Complete and Save the Mission File

An example of our tutorial mission is shown in the exhibit below.


The mission starts at Waypoint 1, note the elevation is set at 80 m above the drone start elevation. The first leg between Wapoint 1 and 2 is 329 m. Note the direction pointer (heading) on the waypoint; it is pointing to Waypoint 2, etc. The total mission is approximately 1.6 km and the time of the mission is estimated to be 7 minutes based on the drone speed of 5 m/s.

Once the mission file is saved to the Litchi cloud server it will be available to your mobile phone in the field when you select the Waypoint mission as the option on your Litchi app.

The results of this tutorial mission will be added to this blog once it is completed.



Map Pilot Pro (Maps Made Easy) TBD


DJI Mini Flight Checklist

  • Charge all components, batteries, controller, tablet
  • Update firmware if not done
  • Download DJI firmware for P3 Pro or Advanced
  • Unzip file, copy bin to SD card root from drone
  • Install SD back on P3 (powered off) drone first, Controller off , props off
  • Power up 25 minutes to complete (beeps)
  • Complete power off P3, remove SD
  • Install on PC review log txt file, Result: Success good
  • Update Controller. Note: Only from DJI Go application. Do not use USB option.
  • Bin file in drone SD card will update batteries for P3 drone
  • Green light on controller and drone 
  • If red on controller need pin on P3 to rebind.




Video Tutorials





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