How to Plan an Oblique Mission with DJI Pilot 2


Before planning an oblique mission, please contact your Propeller customer success engineer. Vertical face imagery is a feature that must be turned on before uploading your data to the platform. 

While the Propeller Platform works best with standard 2D missions, there are certain cases where an oblique mission produces results that more accurately represent the actual conditions of your site, like vertical construction progress. In these situations, we recommend flying an oblique area route mission. An oblique area route mission involves flying a main flight path to collect nadir photos in addition to multiple subpaths facing towards the center of the site to collect oblique photos. Keep in mind that this method requires more flight time and battery power than a standard 2D Area Route mission of the same site.

With the DJI Pilot 2 app (Matrice 300/350 RTK and Mavic 3 Enterprise), it’s also possible to combine Mapping and Oblique data collection into one flight path by enabling the Smart Oblique option on a mission. However, this option is only recommended if time/battery constraints prevent you from flying a full Oblique mission, as it produces less than optimal data.

Oblique Mission Planning

1. Power on your remote controller, ensure that you’re connected to WiFi, and enter the DJI Pilot 2 app.

2. From the DJI Pilot 2 main menu, tap Flight Route.

DJI Pilot 2 Flight Route.png

3. Tap +, then Create a Route.

DJI Pilot 2 Create A Route.png

4. Tap Area Route.

DJI Pilot 2 Area Route.png

 5. Locate your site by panning around the map and using two fingers to adjust the zoom.

6. Tap along the boundary of your site to create a polygon encompassing your mission area. You can tap and drag existing points along the edge to fine-tune the boundary. 

7. Once your polygon boundary is set to your mission area, tap the blue circle/check mark at the top left to configure your mission settings.

8. Select the appropriate camera type for your mission and tap OK

9. Review the table below to ensure your mission settings align with our recommendations and your use case.

Mission Settings Set to Question to Ask Yourself Reason
Camera M3E Series - M3E - WIDE Which camera am I planning on using for this mission? The mission parameters will be different for different lens, so make sure this is set accurately.
Collection Type Oblique Collection Do I need vertical faces captured in my model? Select Oblique Collection if you need vertical faces to be captured in high detail. This will ensure your mission collects oblique data necessary for vertical imaging.
Ortho/Oblique GSD Default Do I need to achieve a specific ground sample distance for this flight? View the GSD estimate to get a sense of what resolution to expect with the current settings. Keep in mind that manually increasing or decreasing the GSD value will alter other mission settings such as flight route altitude.
Smart Oblique Disabled Do I want to combine oblique and nadir photo collection in a single flight band? Smart Oblique can help reduce flight time by switching the gimbal angle to collect both nadir and oblique photos in a single flight band. Optimal data collection requires separate oblique and nadir flight bands to be flown. Disable this for the best results.
ASL/ALT Relative to Takeoff Point (ALT) What elevation is my target altitude referenced to? Unless you are referencing altitude above Sea Level (ASL) in the EGM96 geoid model, set this to ALT.
Route Altitude 250-400ft (80-120m) How high should I fly compared to the takeoff point? Route altitude is a balance between how quickly you would like to complete your survey (higher makes it faster) and the ground sampling distance that you need. This range satisfies this balance.
Safe Takeoff Altitude Above Highest Obstacle Are there obstacles in my takeoff area? Set the Safe Takeoff Altitude to be higher than the tallest obstacle in your area. This will ensure that the drone flies straight up until it is above the obstacles before traveling to your mission start point.
Speed Max Speed Allowable* How fast should I fly? *Unless you're trying to reach the required 10min mission time, increase the speed to minimize overall flight time. In low light conditions, reduce the speed and the shutter speed to ~1/800.
Course Angle User Preference What direction should I fly to cover the survey area? Adjusted with the slide. Fewer turns means more area covered per battery.
Upon Completion Return To Home What should I do after completing the mission? Once the mission is complete, the drone will make its way back to the home point automatically.

 

Advanced Settings Set to Question to Ask Yourself Reason
Target Surface to Takeoff Point 0 Is the terrain I want to survey at a different altitude than my homepoint? Unless the terrain you are surveying is at a very different altitude than your takeoff point, leave this setting at 0.
Side and Front Overlap Ratio (Regular and Oblique) ~80% How much should each of the images overlap each other? Set all 4 overlap ratio settings to ~80%. This provides enough overlap to stitch the images together and build a contiguous model. If necessary, you can reduce the overlap slightly to reduce your flight time and number of photos taken, but don't set this lower than ~70%.
Margin 0 How much margin do I want to leave around the survey area? Provided that your flight boundary covers the entire area you wish to survey, you don't need any margin.
Photo Mode Distance Interval Shot What metric is used to capture images? Distance shooting allows the drone to capture images with consistent overlap.
Route Start Point User Preference Where do I want your mission start point to be located? Tapping the points on your mission boundary will allow you to set the start point location and update your flight route. Conserve battery by selecting the most ideal start point relative to the takeoff location.
Speed (Oblique) Max Speed Allowable* How fast should I fly? *Unless you're trying to reach the required 10min mission time, increase the speed to minimize overall flight time. In low light conditions, reduce the speed and the shutter speed to ~1/800.
Takeoff Speed User Preference How fast should the drone take off? Faster takeoff speeds will slightly reduce the battery voltage but may be necessary on active sites.

10. Tap the save icon on the left side of the screen to save your mission.

Now that your mission is saved, set the camera specific settings.

1. Tap on the camera preview box at the bottom left corner of your screen to switch to camera view. 

2. Select the camera settings menu button.

3. Ensure that the camera is set to capture single photos. If it’s set to Video, tap the toggle switch on the right side of the screen below the menu button to switch it back to Photo mode.

Mission Planning Live Camera View 2.png

4. We recommend the settings listed below when planning Oblique missions. These settings are the same as those used for a 2D mission.

In winter or low light conditions, there are special considerations to make. You may need to slow down the flight speed of your drone to less than 10m/s and adjust the shutter speed to 1/800 or 1/500 to allow enough light to hit the sensor.

Failure to do this can result in a high ISO and will reduce the quality of the images you capture.

Mavic 3 Enterprise Settings

M3E Camera Settings Set to Question to Ask Yourself Reason
Image Ratio 4:3 How much of the image should I delete? 4:3 deletes nothing, utilizing the whole sensor.
Image Format JPEG How should the images be saved? Images must be in JPEG format to upload to Propeller.
Timestamp Disabled Do I want to timestamp manual photos? All images taken as part of the mission will automatically be timestamped. This setting only applies to manual photos and is not relevant in this case.
Lock Gimbal While Shooting Enabled Do you want the gimbal to lock in place while it takes a photo? This will help prevent blurry images.
Mechanical Shutter Enabled Do I want my camera to use the mechanical shutter? A mechanical shutter uses the conventional front and rear shutter curtains at the front of the sensor. Not using the mechanical shutter will introduce distortion.
Dewarping Enabled Should dewarping be applied by the camera? This helps reduce distortion at the edges of images. Enable this on the M3E WIDE camera for the best results.
Mode S (Shutter) How should the exposure be controlled? To avoid motion blur. Shutter mode tells the camera that a fixed shutter speed must be used. The camera can adjust the exposure with apeture and ISO.
Shutter Speed 1/1000 How fast should the shutter close? 1000 is usually a good place to start for sunny conditions. In low light conditions, reduce the shutter speed to ~800 and lower the speed.

 

Double-check your settings in the Preflight Checklist and ensure Dewarping is turned ON for best results when using the Mavic 3 Enterprise. The Preflight Checklist will appear when you start your mission.

Matrice 300/350 RTK Settings

M300/M350 Payload & Camera Settings Set to Question to Ask Yourself Reason
Focus Mode First Waypoint Autofocus How do I want my camera to focus on my site? Focus problems may cause motion blur.
Dewarping Disabled Should dewarping be applied by the camera? When using the Zenmuse P1 camera, disabling this results in more accurate processing.
Image Ratio 3:2 How much of the image should I delete? 3:2 deletes nothing, utilizing the whole sensor. Everything else deletes data.
Image Format JPG How should the images be saved? Images must be in a JPG format to upload to Propeller.
White Balance Set to conditions What conditions should I accomodate for? Adjust the setting to reflect current weather conditions. Setting the white balance incorrectly will result in poor stitching and/or inaccurate coloring of your model.
Mechanical Shutter Enabled Do I want my camera to use the mechanical shutter? A mechanical shutter uses the conventional front and rear shutter curtains at the front of the sensor. Not using the mechanical shutter will introduce distortion.
Mode S (Shutter) How should the exposure be controlled? To avoid motion blur. Shutter mode tells the camera that a fixed shutter speed must be used. The camera can adjust the exposure with apeture and ISO.
Shutter Speed 1/1000 How fast should the shutter close? 1000 is usually a good place to start for sunny conditions. In low light conditions, reduce the shutter speed to ~800 and lower the speed.

These camera settings are independent of the mission settings and will be saved to your drone, but it’s still a good practice to verify the settings before each flight.

See our best practices for drone surveying to learn more about optimal flight settings.

Tips for Flying Smart Oblique Mapping Missions

  • Only fly a Smart Oblique Mapping mission if time and/or battery constraints prevent you from flying a full Oblique mission.
  • Fly a standard Mapping mission to cover the entire site first. 
  • Only fly the Smart Oblique mission over the areas of interest of your site if there is no need to do the entire flight. For example, don't waste time flying flat areas. 
  • Your flight needs to be at least 10 minutes long, per battery, to obtain good positioning data. 
  • The most common use of Oblique missions is to produce clear and detailed images of vertical features, such as a pit wall or building facade. If you have questions about when and how to use Oblique missions, please contact Propeller Support.

I still can't do it!

We wrote these articles to equip you with everything you need to get the job done on your own, but we understand that sometimes this isn't sufficient.

If you're stuck, the Propeller hardware support team may be able to help. You can contact them by emailing hardwaresupport@propelleraero.com.au.

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