This article covers the basics of planning lidar and photogrammetry missions with the DJI M300/M350/M400 drones and Zenmuse L1/L2/L3 sensors.
L1/L2/L3 Lidar
Lidar is a great option if a ground model is needed for a vegetated area. These specific settings will cover recommendations for data capture in vegetated areas, but different settings may be needed depending on the environment.
|
💡 Tip: It should be noted that ideal lidar data collection settings vary from site to site, and a couple of key settings should be considered. While our recommendations are a good starting point for a bare earth model, it is good to be mindful of variations in vegetation that necessitate changes in flight and payload settings.
Return mode dictates the number of times a pulse is sent and received by the sensor: |
1. To begin, power on the controller to access the DJI Pilot 2 app.
2. Connect to a WiFi network or hotspot to ensure base maps will load to assist with mission planning.
3. From the DJI Pilot 2 main menu, tap Pilot 2.
4. Tap Flight Route
5. Tap the + at the top-right and select Create a Route.
6. Select Area Route.
7. Locate your site by panning around the map and using two fingers to adjust the zoom.
8. Drop a pin to start creating your survey area by tapping on the screen on the boundary of your site.
To move a pin, tap and hold to select it and drag the pin around with your finger. You can delete the selected pin by tapping the trash icon or by double-tapping on the pin.
9. After points are dropped to define the mission's boundary, tap the check mark at the top-left. If the settings don’t appear, tap the double arrows at the top-right portion of the screen to expand them.
10. Navigate through the settings listed below to set up your mission. Remember that our recommendations differ somewhat between the L1, L2, and L3 sensors.
| Mission Setting | Set to | Question to Ask Yourself | Reason |
| Drone / Camera |
M300/M350/M400 RTK L1/L2/L3 - Lidar Mapping |
Is this a lidar mission or a photogrammetry mission? | Both lidar and photogrammetry missions can be flown with the L1/L2/L3. |
| Collection Type | Ortho Collection | N/A | Select Ortho Collection to collect straight-down photos during the mission. |
| Ortho 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 Ortho GSD value will alter other mission settings such as route altitude. |
| Altitude Mode | Relative to Takoff Point (ALT) | What elevation is your target altitude referenced to? | Unless you need Terrain Follow or you are referencing to altitude above Sea Level (ASL) in the EGM96 geoid model, set this to ALT. |
| Route Altitude |
L1/L2: 200ft (60m) L3: 200ft (60m) - 300ft (90m) |
How high should I fly relative to the takeoff point? | Collecting lidar above 200ft (60m) with the L1/L2 can impact accuracy of the data. If using the L3, altitude can be increased to a maximum of 300ft (90m) if speed is reduced to 10mph (4.5m/s) or lower to compensate for the reduced point cloud density. |
| Elevation Optimization | Disabled | Is my terrain or altitude expected to vary during flight? | When enabled, the drone will take a few oblique images at the end of the flight. You do not need these to process your data with Propeller. |
| Safe Takeoff Altitude | Above any obstacles on site | How high should the drone be before it can safely fly to the start point? | If there are any vertical obstacles between your takeoff location and the starting location, consider raising this elevation. |
| IMU Calibration | Enabled | N/A | The drone will perform a calibration by flying forward 100ft (30m) and backward 100ft (30m) at the beginning of each flight line. This is necessary to generate a highly accurate model. |
| Efficiency Mode | Disabled | Is maximum accuracy your main concern? If so, leave this setting disabled. | If this setting is enabled, the drone will perform fewer IMU calibrations, causing a 10%- 30% decrease in accuracy. |
| Speed | Maximum of 20mph (9m/s) | Should I slow the drone down? | To ensure penetration through dense vegetation with lidar, decrease your speed to increase point cloud density. When flying the L3 above 200ft (60m), use a maximum speed of 10mph (4.5m/s). |
| Course Angle | User Choice | What direction should I fly to cover the survey area? | Adjust for an efficient flight path and minimal lines. |
| Upon Completion | Return to Home | What should I do after completing the mission? | Once completed, the drone will make its way back to the home point automatically. |
| Advanced Setting | 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 home point? | Unless the terrain you are surveying is at a very different altitude than your takeoff point, leave this setting at 0. |
| Side Overlap | 50% | How much should each image overlap with other images? |
Insufficient overlap can result in holes in the orthophoto and lidar point cloud. Our recommendations will produce consistent results without capturing unnecessary data. |
| Forward Overlap | 80% | N/A | N/A |
| Margin | 0 | How much margin do you 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 interval shooting allows the drone to capture images with consistent overlap. |
| Custom Camera Angle | Disabled | N/A | Keeping this setting disabled will ensure your camera angle stays nadir (-90) and ideal for mapping. |
| Route Start Point | User Preference | Where do you 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. |
| 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. |
| Payload Setting | Set to | Question to Ask Yourself | Reason |
| Return Mode | Set to Conditions | Is my site heavily vegetated? | If a site has less vegetation (grass/none), single or dual return will suffice. If a site has denser vegetation, use a higher return mode for a denser point cloud. |
| Sampling Rate | L1 - 160kHz L2 - 240kHz L3 - 350kHz (Normal Sampling Rate) |
How far away is the surface I'm surveying? | This value affects the point density and level of detail of the lidar data. Use the recommended sampling rate for your sensor for best results when flying at our recommended altitudes. |
| Scanning Mode | L1/L2 - Repetitive L3 - Linear |
Does the site include heavily vegetated areas? Are there complex structures I'm interested in over accuracy? | The repetitive and linear scaning modes are suitable for high accuracy terrain mapping. The frame of view of the sensor in narrowed while increasing the accuracy of points. By selecting non-repetitive, the sensor will have a much larger frame of view, but will be less accurate. |
| Photo Resolution (L3 only) | 6K | N/A | When flying at or below 300ft (90m), 6K photo resolution is recommended. |
| RGB Coloring | Enabled | N/A | If RGB coloring is disabled, Propeller will be unable to process the mission data. |
| Camera Slider Bars | Set to | Question to Ask Yourself | Reason |
| Image Ratio |
L1/L3 - 3:2 L2 - 4:3 |
How much of the image should I delete? | Utilize the whole sensor. |
| Image Format | JPG | How should the images be saved? | Images must be in a JPG format to upload to Propeller. |
| 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. |
| White Balance | Auto | What conditions should I accommodate 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. |
| Dewarping | Disabled | Should dewarping be applied by the camera? | This will help improve the accuracy of your data. |
11. After you have inputted all the settings, tap the save icon.
If you are flying a site with a published coordinate system, we recommend the same ground control practices outlined in our ground control recommendation article.
If you are flying a site with a localized coordinate system, you will need a minimum of 2 GCPs, regardless of site size, while still following our GCP recommendations for published sites.
If you are using GCPs that are not AeroPoints in your LiDAR data collection, then they must be highly reflective.
Some images may be removed in the production of the orthophoto due to poor quality or insufficient overlap. We recommend customers verify that AeroPoint / ground control placements are within the flight boundary to prevent their removal from the overall survey deliverable.
L1/L2/L3 Photogrammetry
The Zenmuse L1, L2, and L3 can also be used for standard photogrammetry without lidar. For the best results with the Zenmuse L1, we recommend flying distinct lidar and photogrammetry missions rather than combining the data collection in a single flight. (This is not necessary for the Zenmuse L2/L3).
Begin by creating a route as outlined above in steps 1 through 9.
1. Once your mission boundary has been placed, select the L1/L2/L3 Camera Model and Photogrammetry Lens.
2. Adjust the settings based on our recommendations listed in the table below. If you encounter settings in the app not mentioned in this table, leave them at their default.
| Mission Setting | Set to | Question to Ask Yourself | Reason |
| Drone / Camera | L1/L2/L3 Photogrammetry | Which camera are you planning on using for this mission? | The mission parameters will be different for different lens, so make sure this is set accurately. |
| Collection Type | Ortho Collection | Do I need vertical faces captured in my model? | Select Ortho Collection if you do not need vertical faces to be captured in high detail. |
| Ortho 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 Ortho GSD value will alter other mission settings such as flight route altitude. |
| Altitude Mode | Relative to Takeoff Point (ALT) | What elevation is your target altitude referenced to? | Unless you are referencing to altitude above Sea Level (ASL) in the EGM96 geoid model, set this to ALT. |
| Route Altitude | 200-400ft (60-120m) | How high should I fly relative to the takeoff point? | The height 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. |
| Elevation Optimization | Disabled | Is my terrain or altitude expected to vary during flight? | When enabled, the drone will take a few oblique images at the end of the flight. You do not need these to process your data with Propeller. |
| Safe Takeoff Altitude | User Preference | Are there obstacles in my takeoff area? | Set the Safe Takeoff Altitude to be higher than the tallest obstacle in your area. |
| 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 completed, the drone will make its way back to the home point automatically. |
| Advanced Setting | 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 home point? | 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 | ~75% | How much should each of the images overlap each other? | This provides enough overlap if some images are missing or poor quality while still building a contiguous model. The lower the detail on the surface below, the higher your overlap should be. If you have a large area to survey, you can look at reducing the horizontal overlap (no lower than 60%) to increase the area you can cover per battery. |
| Margin | 0 | How much margin do you 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. |
| Custom Camera Angle | Disabled | N/A | Keeping this setting disabled will ensure your camera angle stays nadir (-90) and ideal for mapping. |
| Route Start Point | User Preference | Where do you 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. |
| 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. |
3. Tap the save icon to save your settings.
4. Navigate to the camera settings by tapping the live camera view. The map and camera view will switch places.
5. Adjust the camera settings as described in the table below. When you encounter settings in the app not mentioned in this table, leave them at their default.
| Camera Setting | Set to | Question to Ask Yourself | Reason |
| Mode | S (Shutter Priority) | How should the exposure be controlled? | To avoid motion blur. Shutter priority tells the camera that a fixed shutter speed must be used. The camera can adjust the exposure with aperture and ISO. |
| Auto Exposure (AE) | Unlocked | Can the camera auto-adjust exposure? | In order for the camera to be able to adjust the exposure with aperture and ISO, this needs to be unlocked. |
| Shutter Speed | 1/1000 | How fast should the shutter close? | 1000 is a good place to start for sunny conditions. In low light conditions, reduce the shutter speed to ~800 and lower the speed. |
| Focus Mode | AFC | N/A | PLEASE NOTE: The drone may automatically switch to Manual Focus (MF) at the start of each mission. This is expected, and no user input is required. |
| Camera Slider Bars | Set to | Question to Ask Yourself | Reason |
| Image Ratio |
L1/L3 - 3:2 L2 - 4:3 |
How much of the image should I delete? | Utilize the whole sensor. |
| Image Format | JPG | How should the images be saved? | Images must be in a JPG format to upload to Propeller. |
| Lock Gimbal While Shooting | Enabled | Do you want the gimbal to lock in place while it takes a photo? | Leave this on its default setting. 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 | Disabled | Should dewarping be applied by the camera? | This will help improve the accuracy of your data. |
Note that in winter, or low light conditions, there are special considerations to make. You may need to slow down the flight speed of the craft (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.
6. Double-check your settings in the Preflight Checklist and ensure Dewarping is turned OFF for best results. The Preflight Checklist will appear when you start your mission.
Check the airspace on your site before you arrive, and remember to charge your AeroPoints and drone batteries before your mission.
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.
Related to