The 5 Best Drones for Mapping and Surveying
Of the many commercial uses of drones, mapping and surveying seem like some with the most natural fit. By using a drone, surveyors no longer need to spend several days or weeks walking through the survey area and taking manual measurements. Not only do drones make surveying jobs easier, but they can also produce data and models that are more accurate.
However, doing a drone survey is going to take more than just buying any standard commercial drone. Not all drones are made for the job, so here’s a short list of the best drones for mapping and surveying
What to look for in a mapping and surveying drone
To help us narrow down the wide selection of commercial drones, let’s look at the qualities we should look for in a mapping survey drone. These qualities prioritize both the quality of data that the drones can collect as well as the ease with which they can be used for large-scale aerial surveys.
1. Fixed-wing or multirotor?
Although multirotor drones are more common nowadays, mapping surveys can also benefit from the unique capabilities of fixed-wing drones. Choosing one over the other will depend on your budget, the size of your survey area, and your level of expertise as a drone pilot.
Multirotor drones are much easier to fly and maneuver, mostly because they can hover in place. Since they are so common nowadays, they are also much cheaper compared to professional-grade fixed-wing drones. However, they suffer in terms of battery efficiency as they rely on rotors to generate both lift and propulsion. If you’re surveying an area that only measures a few acres wide, then a multirotor drone may be the practical choice.
Fixed-wing drones truly shine if you are surveying a few hundred hectares of land. The design of fixed-wing drones allows them to generate lift by the mere act of gliding through the air. Since their rotors are only responsible for providing propulsion, they can stay airborne far longer on a single battery cycle. However, they also need a more skilled pilot at the helm.
2. Autonomous flight capability
More often than not, aerial mapping surveys will require that you fly over an area multiple times to ensure data consistency and accuracy. To do this, you must ensure that the drone flies along the same flight path every single time. Doing this manually is virtually impossible, so you’re going to need to use a drone that can be programmed for autonomous flight.
Autonomous flight isn’t a feature that you can just activate with any drone. You will probably need to use another software (such as Litchi) to create these flight paths, which will then be transmitted to the drone’s remote controller. By removing heavy pilot input, errors due to human lapses can be avoided.
3. Long battery time
It’s not unusual for mapping surveys to cover areas that are several hectares large. Even with the speed with which drones can fly, a standard drone can’t finish an entire survey on a single battery cycle. Thus, there will certainly be a need for the drone to fly back to a designated landing spot so that its batteries can be swapped.
As you can imagine, landing and deploying the drone multiple times in a single survey will take lots of precious minutes. To optimize the time that you spend in the field, you will want a drone that can fly for at least 30 minutes uninterrupted. This is pretty much a standard number for most modern drones.
4. 4K camera
Photogrammetry is the most common technique used for aerial surveying. The technique uses a series of overlapping geotagged photos taken by the drone to infer the dimensions of all the features on the ground. Although photogrammetry has limitations, it’s a widely favored option because of how accessible and inexpensive it is.
The key to data quality in photogrammetry is the resolution of the camera. You will want to use a camera that can capture as much of the fine details on the ground as possible, allowing the software to recreate these features during 3D modeling. Cameras that can capture 4K videos and 12 MP photos are standard nowadays, but you can go for as high a resolution as available.
5. RTK compatibility
All drones that are commercially available today come with a built-in GPS receiver to allow for locational tracking. This GPS feature provides flight stabilization as well as the tracking that the drone needs for autonomous flight. When doing mapping surveys, the GPS receiver also automatically geotags photos. By embedding the photos with spatial data, the mapping software can recreate an entire 3D model by “stitching” the photos together.
Depending on several conditions, GPS data can have errors of up to a few meters. While this may not be significant to some applications, fields like urban planning and construction may benefit from more accurate measures.
In recent years, drone manufacturers have addressed this problem by integrating RTK technology into mapping drones. RTK stands Real-Time Kinematic, a method by which GPS data can be improved by differential measurements. RTK relies on a constant correction of GPS data relative to a fixed ground station. Through this technique, locational accuracy can be improved to centimeter-level.
RTK drones provide a huge jump in terms of data accuracy for mapping and surveying. However, the upgrade from standard GPS to RTK will also be very expensive.
6. Interchangeable payload
While photogrammetry is the more common mapping method used, it’s far from being the best. If you need more detail in your model, then an alternative would be to use a Light Detection and Ranging (LiDAR) sensor. This sensor emits pulses of light that bounce off solid objects in the survey area. By calculating for the time it takes for these pulses to return to the sensor, LiDAR more accurately determines the size and shape of individual features.
Drone mapping technology can even be combined with other imaging technologies such as thermal imaging and multispectral imaging to generate a variety of data maps. This has proven useful in several industries, from the management of crop farms to surveying of utility pipes.
Drones that come with built-in LiDAR sensors or thermal cameras are rare. If you want these functions, you will have to go with third-party accessories and a drone that can accommodate different types of payload. Such drones are certainly at the high-end and much more expensive than many commercial drones.
Although mapping is a highly technical application of drones, it doesn’t exactly take a highly sophisticated drone to do the job. At the minimum, you’ll need a drone with a good camera, autonomous flight capabilities, and a GPS receiver. Scaling up operations with more advanced gear will require a huge investment but will also allow you to charge premium rates.
Top 5 best drones for mapping and surveying
For a very long time, the Phantom 4 drone from DJI was considered as the standard of professional-grade drones. When the RTK version of the Phantom 4 was released two years ago, it instantly changed the game as far as mapping professionals were concerned. Here was a drone that came with the industry-defining features of the Phantom 4 and further augmented with RTK technology.
The Phantom 4 RTK retains all the best qualities of the standard Phantom 4 – a 1-inch CMOS sensor, a 3-axis gimbal, and a 5870 mAh battery that can keep the drone airborne for up to 30 minutes. Located at the top of the drone is the characteristic RTK module. Combined with the D-RTK2 ground station, this drone can collect spatial data at centimeter-level accuracy.
The Phantom 4 RTK also comes with an upgraded controller with a hot-swappable battery, a slot for a microSD card to store survey data, and an option for 4G connectivity for cloud-based backup. The special GS RTK app was developed specifically for this drone, allowing for intuitive flight planning and easy execution on the field.
The biggest limitation of the Phantom 4 RTK is the fact that it was not designed to be compatible with a Post-Processing Kinematic (PPK) workflow. It also does not have an interchangeable payload which restricts you to mapping via photogrammetry.
2. Yuneec H520 RTK
The H520 RTK is Yuneec’s entry into the market for mapping drones. Sporting the signature hexacopter build of Yuneec, the H520 RTK offers a wide range of solutions for mapping professionals. As the name implies, the drone comes with a built-in RTK module and a Network RTK base station.
There are a couple of things about the H520 RTK that make it stand out. First off is the fact that it does not have a fixed payload. Yuneec offers a range of high-end accessories for the H520 RTK including the CGOET thermal camera and the E90 20MP high-speed camera. These are sold separately but can certainly expand the possibilities of the drone.
The H520 RTK was also designed to be compatible with a PPK process. PPK is useful when doing mapping surveys in areas where communication between the drone and the ground station is not assured. Instead of doing real-time corrections to spatial data, PPK allows for coordinated data collection so that they can be corrected during post-processing.
3. senseFly eBee X
Few companies have as much experience in aerial mapping as senseFly, so it only makes sense for one of their drones to be included in this list. Our choice is the eBee X, a fixed-wing drone that offers enough flexibility for any mapping needs.
The eBee X is an extremely versatile drone. It can accommodate both PPK and RTK workflows and is compatible with a wide range of payload options both from senseFly and third-party companies. These include the SODA 3D mapping camera and the Parrot Sequoia multispectral sensor, among others.
As we have mentioned, the best thing about flying a fixed-wing drone is the fact that it can stay airborne for a really long time on a single battery cycle. In the case of the eBee X, it can fly for up to 90 minutes uninterrupted – a huge value if you’re surveying a wide area. When it comes to planning your surveys, the eBee X is compatible with the widely used Pix4D suite of mapping platforms.
The last thing you need to know about the eBee X is that it’s very expensive – the drone with the accessories can cost up to $15,000. It’s a huge sum, but we’re sure that lots of drone mapping professionals won’t mind the price for such a dependable and high-quality drone.
Thus far, we have focused on high-end drones that were specifically designed for mapping. However, mapping doesn’t always need to be done with an expensive drone. With a little bit of tweaking and some compromises, even the Mavic Air 2 can do some light mapping work.
The Mavic Air 2 is the latest ultra-portable drone released by DJI and is the follow-up to the massively successful Mavic Air. This upgraded version comes with a camera that can capture 48 MP photos and 4K videos at 60 fps. This is one of the best cameras in the prosumer drone market and is certainly powerful enough for photogrammetry.
Being a small drone, it’s going to be hard for the Mavic Air 2 to cover a lot of ground. This limits the usefulness of the Mavic Air 2 for mapping. If you have several hundred hectares of land to survey, then you might need to get a drone that’s bigger and more robust than the Mavic Air 2.
By far, the biggest challenge of using the Mavic Air 2 in mapping is how to come up with a flight plan. After all, even DJI’s very own DJI Terra mapping software doesn’t support flight planning with the Mavic Air 2. The best hope lies in Litchi, as its developers have said that they are working on compatibility with both the Mavic Air 2 and the Mavic Mini.
Part of the DJI Matrice 200 series, the Matrice 210 RTK is easily one of the most premium drones ever released by DJI. Not only does it have a provision for both an upward and downward gimbal, but it also comes with a built-in RTK module. The Matrice 210 RTK is powerful enough to carry two accessories – perfect for doing a dual visual and thermal mapping survey.
As with other Matrice 200 drones, the 210 RTK is compatible with all Zenmuse cameras. These are some of the best payload options the industry has to offer. The selection includes the XT2 thermal camera, the Z30 zoom camera, and the X4S high-speed camera among others. The drone can also accommodate third-party payloads via the DJI SkyPort V2 adapter.
The flight planning capabilities of the Matrice 210 RTK are far more versatile than other mapping drones. Instead of a standard flight planning software, the Matrice 210 RTK offers programming and customization via the Onboard SDK and Mobile SDK. This gives you virtually endless options for automating the drone’s flight. DJI also offers a separate Payload SDK to control the functions of the camera or sensors.
Between the drone and the accessories, buying a full Matrice 210 RTK setup can cost $10,000 or more. It’s also far from being user-friendly. Investing in a drone like this is a serious business, but a lot of professionals will testify to its value.
Aerial mapping and surveying are some of the most lucrative fields in the era of commercial drone flight. It’s also one of the most technically demanding, creating a huge barrier to entry in terms of skill and technology. While this article doesn’t touch on the skill you need to be a professional drone mapper, we hope that we have pointed you in the right direction in terms of the hardware you’ll need.