Waypoints Mission: plan a flight route and capture photos or videos at waypoints along the route.
Mapping Mission: collect images of an area to reconstruct a 2D model.
Oblique Mission: collect images of an area from multiple camera angles to reconstruct a 3D model.
Corridor Mission: collect images of a corridor (e.g. rivers, railroads) to reconstruct a 2D model.
Detailed Inspection Mission: Set target points on a reconstructed model and a flight route will be automatically generated, allowing the aircraft to capture photos at these target points.

DJI Terra’s Oblique Mission uses 5 flight routes to capture the same amount of data as using 5 cameras simultaneously on a drone. The 5 flight routes correspond to the 5 camera headings – downward, forward, backward, leftward, and rightward.

If you have access to a mobile device that has an internet connection (such as a cellphone), you can turn on the hotspot so that the laptop can be connected to the internet.
If the site where you are operating has no internet signal, you can pre-plan the flight route while you are indoors and have an internet connection, or manually fly the drone around the area to be mapped to set boundaries points to plan flight routes.

In photogrammetry and remote sensing, ground sample distance (GSD) in an aerial digital photo (such as an orthophoto) of the ground is the actual distance on the ground captured as represented by pixels. The unit is cm/pixel.

Yes.

Mission Relative Height in Advanced Settings is the height of the takeoff point relative to the area being mapped. Mission Altitude is the height of the drone relative to the area being mapped, which is also how ground sample distance (GSD) is calculated.

When there is a large difference between the elevation of the takeoff location and the elevation of the area being mapped, you can adjust the Mission Relative Height in Advanced Settings to ensure that the Mission Altitude is determined considering the elevation of the area being mapped.
Please see the attached illustration: If the drone takes off from a 50 m building marked H1 in the illustration, the area being mapped is marked A, and the expected altitude for aerial data collection is 100 m, you can set the Mission Altitude in Basic Settings to 100 m, and Mission Relative Height in Advanced Settings to 50 m.
Similarly, if the drone takes off from H2 to map area B, which is a hill with an elevation of 40 m, and the expected altitude for aerial data collection is 60 m, then set Mission Altitude to be 60m, and Mission Relative Height to be -40 m.

It is recommended to have a forward overlap rate of 80% and a side overlap rate of 70%, which should meet the requirements for most application scenarios. The overlap rate can be increased when the area being mapped has a large difference in elevation to ensure the highest point mapped has enough overlap. When the area mapped is relatively uniform in elevation, the overlap rate can be adjusted lower to reduce the amount of data that needs to be processed, making the mapping mission more efficient. However, it is recommended to keep the forward overlap at a minimum of 65% and side overlap at a minimum of 60%.

It could be that you are operating somewhere with a lot of signal interference or obstructions, which affects the strength of the RTK signal. Try turning off the RTK module and take off manually with the GNSS positioning. Once the drone reaches a height where there is less interference, you can turn on the RTK module and connect to DJI Terra to conduct your flight missions.

Yes.

Phantom 4 RTK (NO-MONITOR RC), Matrice 300 RTK + H20 Series Payloads, Mavic 2 Enterprise Advanced, Matrice 350 RTK, DJI Mavic 3 Enterprise Series (DJI Mavic 3E and DJI Mavic 3T), and Matrice 30 Series

Yes, LAS point cloud files can be imported.

Yes. You should set the coordinate system when you first import the file. If the file uses an arbitrary coordinate system, you need to correct it using third-party point cloud correction software.

No, the aircraft needs to be flown at absolute altitude.

1. The overlap rate is too low. You may re-shoot the images as needed;
2. Make sure “Urban” is selected as the reconstruction scenario.

1. Make sure the RTK data sources are consistent when planning or executing a flight path;
2. Flight paths can only be executed when the RTK is in FIX status. During execution, you may set the first waypoint as the hovering inspection point. The mission must be stopped if the location of the inspection point is incorrect.

1. Generally, you can determine the camera’s 35 mm equivalent focal range through its manufacturer’s official website, packaging or customer service (some manufacturers label it as “equivalent focal range”). Set the camera name, fill in “35 mm equivalent focal length”, and tap the application to complete the configuration.
2. For better modeling results, you may obtain all the camera’s parameters from its manufacturer, such as F, CX, CY, K1, K2, K3, P1, and P2 (take care to distinguish the units “px” and “mm”; note that a fisheye camera has K4), then tap “Advanced Settings”, select the lens type, and fill in all the relevant parameters.
3. If you are unable to obtain all the camera’s parameters (intrinsic, principal point, and distortion parameters) from its manufacturer, you may do so by calibrating through DJI Terra.
A. For calibrating DJI Terra, we recommend using photos of urban scenes (with minimal vegetation) captured on tilted flight paths. The recommended parameters are: flight altitude of 100 m, shutter speed of ≤ 1/400 s, camera distortion correction disabled, tilt angle of -45° (pitch), and 80% forward and 70% lateral overlap rate.
B. After importing the photos, set camera information such as “35 mm equivalent focal range” and perform an aerotriangulation computation, and you will find the camera’s optimization parameters under “Camera Calibration Info” in the Aerotriangulation Report (fill in this information again in DJI Terra and perform another aerotriangulation computation, and you will receive parameters that are more accurate).
C. If you are able to obtain the values of the camera’s F, CX and CY in the “px” unit, you may enter the three parameters in the Advanced Settings (“35 mm equivalent focal range” need not be filled in this time), then perform an aerotriangulation computation. The Aerotriangulation Report will provide all the camera’s parameters at greater accuracy.
D. If the camera’s F, CX and CY values can be obtained in the “mm” unit, its sensor width, height and pixel size must be filled in first (“35 mm equivalent focal range” need not be entered this time), before performing an aerotriangulation computation. The Aerotriangulation Report will provide all the camera’s parameters at greater accuracy.
4. Other third-party software can be used for calibrating the camera. However, note that CX and CY must be defined based on offsets relative to an image’s origin in its upper left corner.

First make sure if the number of images transmitted differ significantly from the number of images shot. If they do not, you may check the log to see if a “relocalization fail” message has appeared. If so, you need to increase the mission altitude as necessary to enhance the overlap rate.

The Field Scenario is designed to capture data from a relatively flat land, for example rice or wheat fields.
The Urban Scenario is designed for areas with buildings of different heights.
The Fruit Tree Scenario is designed for orchards that might have a large variation of elevations and heights.
The 2D mapping algorithms are optimized for the three specific scenarios, so you can choose the one that best fits your mission type.

1. The head of the aircraft did not turn around during data acquisition, and the intrinsic parameter cx or cy of the aircraft is shown in the aerotriangulation quality report as >5% than half the length and width of the images;
2. The locations cover contrasting terrain, with roofs or hilltops captured in the shots, which resulted in a low overlap rate. You may re-shoot the images as needed.

When the reconstruction is complete, TFW and PRJ files are automatically generated in the root directory of the corresponding mission folder.

The location information on aerial images collected by a drone that’s not equipped with RTK is not the most accurate, which will result in a difference between the elevation in the digital surface model (DSM) and the actual elevation.
When conducting missions with the Phantom 4 RTK, if the 2D map is generated with only the Nadir view images collected, the precision of the DSM will be limited, which is why it is recommended to incorporate oblique imagery in building the 2D map to enhance precision. This can be done by setting the gimbal pitch to -45° and circling the point of interest during flight.

There are three options for reconstruction resolution: high, medium, and low, which will generate models at full, half, and quarter resolution respectively. The higher the resolution the better the quality of the reconstructed models. The rough ratio of time consumption for reconstruction at high:medium: low resolutions is about 16:4:1.

The Region of Interest(ROI) function is available. After completion of the aerotriangulation, the reconstruction area can be specified.

The following reconstruction results can be delivered in specified coordinate systems.
Aerotriangulation: an aerotriangulation result file in .xml
2D Reconstruction: dsm.tif, result.tif
3D reconstruction: point cloud files (.las, .ply, .pcd, .s3mb) and model files (.osgb, .ply, .obj, .s3mb, .i3s) is accompanied by a coordinate system instruction file metadata.xml.

Ground Control Points (GCPs) are marked points on the ground with known coordinates and are clearly visible in an image. GCPs can be obtained using photogrammetry methods such as GPS-RTK or a total station.

GCPs help increase the robustness and accuracy of aerial triangulation, check the accuracy of the aerial triangulation against actual measurements, and determine absolute orientation by converting the aerial triangulation result into GCPs in the designated coordinate system.

The GCP data should be in this order: point name, latitude/X, longitude/Y, height/Z, horizontal accuracy, vertical accuracy).Accuracy data is optional. The first row is coordinate data, and each column is separated with a space or a tab. In the projected coordinate system, X represents the East, and Y represents the North

GCPs are used to optimize the result of aerial triangulation. It would take at least three GCPs to ensure absolute orientation for aerial triangulation.
Check points are used to check for the absolute accuracy of aerial triangulation by comparing the error between the result calculated with aerial triangulation and the actual measurements.
It is recommended to use no less than four GCPs for calculation in each target area.
When you have an abundant number of GCPs, you can choose to set some of them as check points to check for accuracy.

GCPs values are used in aerial triangulation, and the accuracy should correspond to the final absolute accuracy that your project needs.
The smaller the accuracy settings, the stronger the GCP’s contribution will be to the triangulation model.

When computing a point and GCPs have been marked on at least 2 images, the 3D coordinates will be calculated and reprojected onto all images in which the point appears. The difference between the marked point and reprojected point on the image is the reprojection error. the average of different reprojection errors is shown in DJI Terra as the reprojection error.

The 3D error of a GCP refers to the spatial difference between its measured coordinates and 3D coordinates obtained by conducting space intersection with the elements of interior and exterior orientations of the image.

Given that the coordinate system in which aerial images and GCPs have been acquired can be converted using DJI Terra, i.e. the images and GCPs use the same coordinate system geodetic datum:
a) For images with high positioning accuracy, for instance, ones acquired using the Phantom 4 RTK, GCP projections will not be far off from actual measurements. Mark the GCPs with reference to their projected results on the image, and then click “aerial triangulation” on the screen.
b) For images with low positioning precision, you can run aerial triangulation first with the imported images that contain GPS information, and then import the measured coordinates of the GCPs. After the first triangulation, you can proceed with marking the GCPs and run an optimization by pressing “optimize” on the screen.

An optimization is done to improve results of aerial triangulation. If a triangulation is done immediately after marking GCPs, check points will also be used in the calculation, which is not ideal. A better process will be: aerial triangulation enter GCP coordinates and mark them against projected coordinates on the image optimize. By doing so, GCPs are used to improve the accuracy of aerial triangulation.

The accuracy of aerial triangulation and optimization are affected by three factors: error in GCP marking, error in coordinate measurement, and the distribution and number of GCPs within the mapping area.
We recommend you choose at least four GCPs distributed evenly across the target area. Each GCP should appear in at least four images at different locations, and avoid having it near the edge of an image.

1. If you are looking to acquire results in a particular height or coordinate system (e.g. a local height or coordinate system that might not be included in Terra’s existing database) without GCPs.
2. If you are looking to process POS data and GCPs in the same height or coordinate system, you might need to import POS data and GCP data that have already been converted to said system.

The coordinate system setting of the POS data needs to correspond to the actual system written in the data. Any height errors need to be adjusted for in the settings. You can preview the height values after adjusting all the POS import settings.

1. Set to default DJI Terra accuracy. If the images contain RTK information and it is fixed, DJI Terra will read this data automatically and set the accuracy as follows: horizontal accuracy: 0.03 m, elevation accuracy: 0.06 m. If no RTK information is available or if it is not fixed, horizontal accuracy will be set to 2 m and vertical accuracy 10 m.
2. Set accuracy values manually. Edit the horizontal and vertical accuracy values into the POS data files and choose the corresponding column in in the POS import settings.

These images will not be included in aerial triangulation calculations.

Generally, you should keep it on, but turn it off if the image POS data and the GCPs are not in the same height system.

Square.

Yes.

No, the result of map grid output will be additionally generated

Starting from the top left corner of the area covering the largest extent of the 2D map, divide it by the set map grid length.

A suffix is added to the name of the result file (such as_1_2), where 1 represents X-axis and 2 represents Y-axis

Stored in the mission folder:
(1) Mission Namemapdsm_tiles
(2) Mission Namemapresult_tiles

The map grid result will have the BigTIFF parameter if its size is over 4 GB, the result will have no such parameter if its size is less than 4 GB.

1000 px.

Please refer to Preparation Before Using DJI Terra available on the download page.

Please refer to Preparation Before Using DJI Terra available on the download page.

It is determined by the device with the largest memory in the device participating in cluster computing. 1 GB of idle memory can process approx. 6,000 images).

Each computer connected to a local network is either a control device or a worker device. A control device assigns reconstruction missions (and also undertakes part of the computing work), while reconstruction algorithms run mainly on worker device.

Binding is not necessary. Worker devices can be replaced as needed.

Yes. For details, please refer to Preparation Before Using DJI Terra.

It is used to store original image data, temporary outputs and reconstruction outputs.

1. If Aerotriangulation Cluster Computation is enabled, DJI Terra will automatically estimate the computing speed of the standalone and the cluster and select the more efficient option. If this feature is disabled, DJI Terra will perform the reconstruction in standalone computing mode.
2. It is recommended to enable Aerotriangulation Cluster Computation when the number of photos exceeds 8,000 and three or more worker devices participate in reconstruction.

Zenmuse L1 point cloud processing is a free feature, but if the point cloud accuracy optimization is desired, you need to purchase the license for the Pro version or higher. Zenmuse L2 point cloud processing is a free feature, and the point cloud accuracy can also be optimized for free.

No.

1. Point cloud effective distance: The point cloud that exceeds the distance from the LiDAR will be filtered during post-processing.
2. How to set up a point cloud effective distance: Estimate the maximum straight-line distance between the location of LiDAR and the corresponding target area when collecting data.
3. Under which scenes to set up: When reconstructing a closer measuring area, and when distant background areas are inevitably collected, you can set up an effective distance to get a better result for point cloud.

1. Point cloud accuracy optimization: Optimize point cloud data scanned at different times to make the overall point cloud accuracy higher.
2. When to turn on point cloud accuracy optimization: When it is off, if the results contain obvious layer malposition, turn on the point cloud accuracy optimization feature to fix the problem.

You are recommended to separate it into multiple tasks for processing.

The reflectivity of the measured target is between 0 – 255, where 0 to 150 correspond to the reflectivity within the range of 0 to 100% in the Lambertian reflection model; 151 to 255 correspond to the reflectivity of target objects with retroflection properties.

The 3D coordinates, RGB color, reflectivity, GPS timestamp, number of returns, the actual return number, and scanning angle of the points are recorded, along with the total number of points corresponding to each return, the software and version corresponding to the generated results, and the geographic coordinate system.

.pnts, .las, .s3mb, .ply, and .pcd

The calibration frequency varies according to actual usage. When the point cloud post-processing results are layered, inaccurate color rendering, or the device is accidentally dropped, you can use the Zenmuse L1 Calibration mode for processing, and then export the calibration file to the remote control for device calibration.

It is recommended to use DJI Pilot to plan the route for collecting calibration materials. The requirements for route planning are as follows:
1. Surveying area: A surveying area at least 300m X 300m with obvious texture features and building facades.
2. The oblique photography route is recommended, with the Repeat Scan Mode enabled, a route speed ≥10m/s, a route height of 100m, a forward overlap ratio of ≥80%, and a side overlap ratio of ≥60%.
3. Model coloring must be enabled (when collecting visible-light photos).
4. You can use either RTK or PPK.

1. Checkpoints can be set up in the surveying area, so that you can verify the accuracy of checkpoint based on the calibration route reconstruction results. If the accuracy reaches the engineering project accuracy, the calibration is compliant.
2. Observe whether the coloring of the point cloud results is accurate, and no layered.

The calibration route can be designed using 5-heading tilt-shift photography or traditional 5-route oblique photography.

To achieve a more reliable calibration result, the following parameters are recommended:
– Capturing no less than 500 images
– The front overlap is no less than 80%
– The side overlap is no less than 70%
– The proportion of oblique images is not less than 2/3
– A calibration scenario with a large elevation difference area

RTK is not required, but the quality of calibration results can be verified through RTK in connection with checkpoint layout.

If RTK positioning data is available for calibration route collection, the accuracy of checkpoints can be verified based on the results of the calibration route reconstruction by deploying checkpoints in the survey area. If the accuracy meets the required engineering accuracy, the calibration meets the standard.

If no RTK positioning data is available for calibration route collection, it is impossible to quantitatively evaluate whether the calibration result meets the standard. However, this can be verified based on the difference between the initial value and the optimized value of camera parameter focal length f and principal points cx, cy for oblique photography reconstruction after camera calibration. If there is no significant difference, the calibration can be considered as meeting the standard.

How often the load device should be calibrated depends on actual use. It is recommended to calibrate the camera using the latest reconstruction calibration file when there is a significant difference between the initial value and the optimized value of camera parameter focal length f and principal points cx, cy in the reconstruction quality report, and the reconstruction result meets the engineering accuracy requirements.

No. Currently RGB images are required for 2D multispectral reconstructions.

Yes, before reconstruction, calibration data can be imported for radiometric correction

Up to three sets of calibration board data are supported.

Yes, the .obj files generated in DJI Terra can be imported into Maya, Blender, SketchUp, and 3ds Max. Look up tutorials for the specific process for each software.

Yes, .b3dm, .osgb, .ply and .obj files generated by DJI Terra are universal file formats and can be embedded into webpages. You can find instructions for embedding each of these formats online.

Theoretically they can be used to reconstruct 3D models although the quality might suffer. They cannot be used to build 2D reconstructions.

Theoretically yes for 3D models, but the results might not be as good as if you were to use DJI drones. The quality of the reconstructions will benefit from GPS or RTK positioning data on the images. Real-time 2D reconstructions are not supported.

1. Check if there has been any hardware changes with the computers bound to the software. Any hard disk location changes or CPU replacements will invalidate the previous binding settings;
2. Check if you have bound any hardware device on a cloud server, such as Alibaba Cloud and Tencent Cloud, which will invalidate the previous binding settings.

1. Check if any other software (or a virus, Trojan horse, adware, etc.) has been installed on your computer that is preventing DJI Terra from establishing an internet connection. This can be solved by resetting the networks of the Windows system.
2. Check if any VPN software has been enabled. If so, disable the VPN or configure the VPN correctly.

You will see the following data in the log:
[GetAvailableFunc] iDate: 1596520841 iCurDate: 1596520513 iEndDate:1596729600
[GetAvailableFunc] Local license out of date.
iDate is the server’s time, and iCurDate is the current time of the user’s computer. The license cannot be used when iDate > iCurDate.
Usually the value of iCurDate should be greater than iDate. It is possible that your computer’s clock is slow. You may try resetting the time. Both Win7 and Win10 support automatic online time calibration. We suggest you enable this feature.