With rapid technological advancements, drones are being used for a wide range of purposes in lots of different industries. One area of application where companies are utilising the power of drones is aerial surveying. There are many industries that are using drones for their surveying and mapping needs these include construction, mining, agriculture, forestry, and environmental research.
Traditional methods of land based surveying is time-consuming, expensive and sometimes risky for those who are tasked with the job. Aerial surveying through drones provides an alternative way for companies to carry out their surveying needs without the disadvantages land based methods.
The benefits of adopting drone technology for various commercial reasons including surveying are huge and companies that are using drones for their operational needs are reaping the rewards.
Whether you are a drone service provider, a professional surveyor or someone who is interested in the application of drones in surveying, this article will provide an overview of what drone surveying is and how it is benefitting different types of industries.
What Is Drone Surveying ?
Surveying is the discipline of determining the position of distinct points and the distance between them on or above the surface of the earth. Surveying plays an important role in many industries where you need accurate maps and measurements of an area of land.
From construction and mining to agriculture and environmental research, companies require a detailed aerial view of sites that they are working on so that they can make informed decisions with regards to planning and implementing those plans.
Traditional methods of land-based surveying require quite a few tools to do the task properly and is quite labour intensive. It is also time-consuming and can take days or weeks to accurately survey a large plot of land.
Drones provide a cheaper and more efficient method for surveying without compromising on quality and accuracy. In many instances, drones may also prove to be the safer option as some terrains will be dangerous for land-based surveying.
Drone surveys and mapping are carried done through photogrammetry; photogrammetry is the science of acquiring accurate data about the physical world through images. These images are then stitched together via photogrammetry software and the end product are resources like maps and 3D models of the area.
From these resources, companies can extract the information they require and make informed decisions with regards to whatever project they are working on.
Benefits Of Drones For Surveying
There are various benefits of drone surveying over traditional methods of using total stations and manned aerial surveying.
For one, drones are easier to deploy, and they are not very hard to fly, anyone with a little training can fly one, although, as they will be used for commercial reasons, the operator will need a CAA/FAA license to fly.
Drones can be flown at lower altitudes than manned aircraft and this results in better image resolution and positional accuracy is not compromised.
Another advantage of surveying with drones is that surveyors can easily access areas of land that are hard to survey with land-based survey equipment. Terrains that are harsh and a risk for people to walk around or areas of land that may be hard to access by land-based means are much easier to survey with drones.
Probably the main benefit that most companies will base their decision on whether to invest in drone technology is the time and cost it takes to complete a drone survey.
Surveying with drones have proven to be more time-efficient and less costly than traditional methods of surveying. Drone surveying requires less manpower and equipment and what usually takes a week to complete can be done in a day or two.
Uses Of Drones For Surveying
According to a survey carried out by cloud mapping company Drone Deploy, the biggest use of drones for their software is from construction companies. Construction companies can formulate a more efficient workflow by adopting drone technology for their surveying and mapping needs. Drones allow construction companies to quickly acquire highly detailed aerial maps of the area they are working on and this will allow them to evaluate lots of different data points. This will help them in every aspect of the decision making process for the project. From the initial preliminary inspection of the land to see its suitability for construction to
Mining & Quarries
Mines and quarries are dangerous places to work but with the help of drones, many of the risks that come with working on a mining site can be mitigated. Drones are being used to create detailed 3D models and maps of mining sites that will help workers in all aspects of mining operations. From initial mining exploration to calculating stock volume, the use of drones in mining is helping mining activities to become more efficient, less risky and help with saving costs and increase ROI.
The use of drone technology is revolutionising the way farmers are managing their day to day tasks. With the aid of different types of camera sensors, farmers can easily survey and map their fields and identify issues such as irrigation problems, pest and fungal infestations and take action as soon as any problems are identified. Data collected through drone surveys are allowing agronomists and agricultural engineers to maximise crop production, use pesticides/herbicides where it is needed, keep waste to a minimum and irrigate the land more efficiently. As drones are cheaper to operate than traditional methods of manned aerial missions, farmers can monitor and assess the health of their crops more frequently and help identify and solve problems quickly.
With our climate changing and bringing with it unusual weather and increasing the rate of natural disasters like flooding, drought, tropical storms and wildfires, drone technology is helping scientists to better understand how to prevent or mitigate the damages these disasters bring.
Digital Assets That Can Be Produced With Drone Surveys
There are different types of assets you can expect from the data that is provided by drones, it comes down to the type of camera being used for the project and the software application used to process the data.
Photogrammetry software can mesh together thousands of drone images and reconstruct an accurate 2D map. These images are tagged with geolocation data and are used in many industries such as construction for urban planning and infrastructure development.
3D Maps & Models
Aerial images can be turned into high-intensity point clouds for 3D reconstruction of the area or object being surveyed. Point clouds have accurate georeferenced points and colour data and the 3D image that is constricted from them are used for many purposes. For example, in the field of construction and engineering, 3D models of areas of land or buildings will be used to make planning and design decisions, cut and fill requirements and progression reports. 3D maps are also useful in the mining industry where companies can use them to accurately calculate stockpile volume and because of the ease with which drones’ can be deployed, inventory can be monitored regularly and managed more efficiently.
Many drones now come with thermal imaging cameras and this expands their capabilities for surveying and mapping. Many industries like construction and agriculture require thermal imaging data to identify abnormal heat signatures. For example, in precision agriculture, thermal maps of crop fields can help farmers identify crops that are not being irrigated properly, detecting germs and disease, soil analysis and estimating crop yield.
These maps are used in agriculture and environmental monitoring, they are created via multispectral cameras and allow farmers and conservationists to monitor the health of crops and vegetation.
Digital Surface Models (DSM)
These are georeferenced with 3D coordinates and are used in city planning/modelling, landscape modelling and other construction/urban planning reasons. DSM provides data for all the features on the surface of the earth including natural and man-made.
Digital Terrain Models (DTM)
Similar to DSM but the man-made and natural features are filtered out and what is left is the data for the bare terrain.
Best Drones For Surveying
This is not a comprehensive list and they are in no particular order, I have listed the multi-coptor drones first because they are the cheapest, while the fixed wing drones like the WingtraOne and eBee X are significantly more expensive. However, fixed wing drones have longer flight times and this makes them more suitable for bigger surveying projects.
If you would like an in-depth analysis of the differences between the most popular drones for surveying,read this case study by Wingtra that carried out a field-test to see which one provided the best results.
#1) DJI Phantom 4 Pro 2 RTK
Probably the most popular surveying drone on the market, the Phantom 4 Pro RTK is a versatile drone with many advanced features that makes it one of the best drones in this field. It comes with a real-time kinematic module for centimetre level positional data which results in survey-grade accuracy for any kind of mapping needs. It comes with a 1-inch 20MP CMOS sensor, 30 minutes of flight time and an omnidirectional obstacle avoidance system.
#2) DJI Phantom 4 Pro Multispectral RTK
The DJI P4 Multispectral drone has been engineered towards collecting image data for agriculture, forestry, and environmental monitoring. The multispectral camera has 1 RGB sensor and 5 other sensors that capture data across the electromagnetic spectrum that is invisible to the naked eye. With these sensors’ agronomists, conservationists and environmental engineers can obtain a lot of data regarding the health of plants, trees, soil etc and make informed decisions with things like pesticide and fertilizer applications. Other features the drone comes with include 27 minutes of flight time and obstacle avoidance technology.
#3) DJI Matrice 300 RTK
This is one of the latest drones in the Matrice series, the 300RTK has a robust and rugged build and with its IP45 rating, it’s a drone that can be flown in extreme weather conditions. It has multiple payload capabilities which makes it a very adaptable drone that can be used in many different industrial applications. Depending on its payload, it has a maximum flight time of 55 minutes, some of the payloads that are compatible with the 300 RTK include the Zenmuse L1 with LiDAR sensor, Zenmuse P1 and Zenmuse H20T which comes with thermal imaging capability. The drone also has AI flight capabilities, a 6-directional sensing system for safer flying and an advanced UAV health monitoring system to keep the drone in optimal conditions.
#4) WingtraOne VTOL Drone
A fixed-wing drone that comes with vertical take-off/landing capability much like a multicopter drone and so there is no need to launch it by hand or any other means. This is a drone that is suitable for large scale surveying and mapping needs, it has a robust build and can be flown in windy conditions. The drone is compatible with multiple payloads which include the Sony RX1RII with a full-frame 42MP sensor and the Micasense RedEdge multispectral camera. It comes with an integrated PPK GNSS receiver from Septentrio for survey-grade positional data with the capability to achieve sub-centimetre level accuracy. It is well-engineered and is built to military-grade standard and has an IP68 rating that allows it to be operated in harsh weather conditions.
#5) eBee X Fixed-Wing Drone
SenseFly’s eBee X is their flagship surveying and mapping drone and is used in a wide range of industries. It’s compatible with multiple payloads including the S.O.D.A 3D camera, the Aeria X with 24MP APS-C sensor, the Duet T thermal imaging camera and the MicaSense RedEdge multispectral camera. It has a maximum flight time of 90 minutes (depending on the payload), which is the best on this list and comes with RTK/PPK modules for greater positional accuracy.
How Accurate Is Drone Surveying?
There are many factors that will influence how accurate a drone survey is, things like the drone’s camera capability, the altitude at which the images will be captured, the requirements of the project, even the weather and area or target to be mapped/modelled can affect overall accuracy.
Things like GSD, which are heavily influenced by the camera sensor specs will also affect accuracy as well as the use of GCP’s and whether the drone has GPS correctional technology like RTK or PPK.
With all that said, drones’ surveys have proven to be very accurate, for example, the WingtraOne VTOL drone, which is one of the best drones for photogrammetry can achieve horizontal accuracy levels of 1cm and vertical accuracy to 2cm.
While DJI Phantom 4 RTK has also shown to have survey-grade accuracy, achieving sub 3 cm vertical and sub 2 cm horizontal accuracy.
Some situations like measuring NDVI in agriculture or analysing the health of vegetation may not require accurate survey-grade measurements and in those cases, you will not need GPS correctional technology to achieve the highest accuracy.
Best Software For Drone Surveying
There are plenty of drone surveying applications that will help turn your drone data into useful digital assets, although this is not a comprehensive list, the drone mapping applications listed below are some of the more popular ones on the market.
One of the leading software developers for drone photogrammetry solutions, Pix4D’s mapping and surveying apps are one of the most robust on the market. It has a bit of a steep learning curve because of its range of features and the sophisticated nature of the software. However, their support is first class and there is a very active community forum as well as in-depth tutorials. There is a 15-day free trial and then you can either choose a pay monthly subscription plan, a yearly license or a one-off fee.
This a drone mapping and 3D modelling software solution that is suitable for small to large and complex mapping projects. It has a wide range of features and all the data is processed in the cloud so there is nothing to download. The software is compatible with most of DJI’s high-end drones as well as WingtraOne, eBee X and Skydio 2. It serves an array of different industries and the data is easy to read and analyse. There are a lot of helpful guides in the form of webinars, ebooks, a forum and regular blog posts. There are three pricing plans with the option to pay monthly or yearly.
This isn’t strictly a tool for just drone photogrammetry, the company has been developing software dedicated to computer vision technology and through years of research, they have gained proficiency in developing algorithms for photogrammetry systems. The software is intuitive, easy to use and comes with a lot of features that will be useful for both amateurs and professional surveyors. There are two versions of this software, standard and professional, the standard version is okay for amateurs who don’t need it for work-related projects, but the professional version comes with a lot more features and is compatible with different type of camera sensors. Both versions come with a free 30-day trial and then a one-time fee.
Site Scan For ArcGIS
This is a complete end to end cloud-based mapping solution for the AEC and mining industry. The software allows drone operators to plan flight missions, manage flight data and process that data to produce 2D/3D maps. It also has a range of tools that will allow you to make sense of the data and share them with colleagues and clients. If you have a fleet of drones, the software will allow you to properly manage your drone operations safely, efficiently and without any hassle.
Get access to advanced mapping and flight planning software that also allows drone service providers to manage their fleet of drones in an efficient and safe manner. PrecisionHawk offers more than just a software solution for drone mapping and analytics, as a member you get access to their network of thousands of professional drone pilots who you can hire to carry out your drone mapping needs. PrecisionHawk also provides a consulting service for your drone business and you can even hire their own team for your drone projects. Their software offering is robust and is used in a variety of industries including agriculture, oil & gas, mining and environmental monitoring.
One of the more recent additions to the drone mapping software market and while it may not be as robust as some of its competitors, it is a DJ product, so you can expect continuous updates and improvements. The DJI Terra allows surveyors to conduct autonomous flight mission and capture aerial data that can be turned into 2D maps and 3D models. It is being used in a wide range of industries including construction, energy, agriculture, mining and government. There is a range of analysis tools to help you with making sense of the data and make better-informed decisions.
Founded in 2014, Propeller Aero provides an end to end cloud-based solution for photogrammetry purposes. It’s a robust platform that allows surveyors to process drone data into accurate 3D visuals and comes with a set of analytics tools to make sense of your 3D digital assets. The system is compatible with a range of drones, however, they do advise that their preferred drone is the DJI Phantom 4 RTK.
Maps Made Easy
A cloud-based data processing software for drone photogrammetry, the website may not look as polished as its competitors, but the software does what it says and allows you to turn your drone images in to valuable digital assets for your project. The software can process image data from different types of sensors like RGB, infrared and multispectral and it has an affordable pricing plan that is not subscription-based.
Photogrammetry vs LiDAR
Creating digital 2D maps and 3D models through images captured by drones is done through a process called photogrammetry.
Photogrammetry is the science of obtaining accurate data about the physical world by capturing and interpreting digital images through different types of camera sensors. These image data can then be processed through photogrammetry software to obtain digital assets like 2D maps, 3D models, point clouds and other types of aerial maps.
It is the most popular and cost-effective way to survey and map areas of land and physical objects.
An alternative to photogrammetry is a system called LiDAR which stand for light detection and ranging. LiDAR is similar to SONAR and RADAR, it scans the area below by rapidly firing laser pulses from its sensor and then calculates how long it takes for the pulse to reflect back to the sensor.
It is a decades-old technology that has only recently become suitable as a payload for commercial drones.
When LiDAR data is processed you get a detailed point cloud that is accurately georeferenced with each point having 3D spatial coordinates. The result is a 3D visualisation of the area or object that has been scanned.
The advantages of LiDAR over photogrammetry are several, for example, laser pulses can penetrate areas of land that are populated with dense vegetation and provide an accurate visual representation of the area below. This is not possible with photogrammetry because images need a lot of light to capture all of the data for a photo.
Also, LiDAR is the best option if you are required to map in a low light environment or at night time because, unlike photogrammetry, it does not require an outside light source.
LiDAR data is tougher to decipher if you are not a GIS professional, whereas a 2D map or 3D model from photogrammetry is easier to understand even for people with little experience with mapping.
Both methods have their pros and cons, however, the biggest deciding factor for most companies will come down to cost and in that case, photogrammetry is the better option as it is much cheaper than LiDAR.
We have seen in this article the benefits of surveying and mapping with drones, drones can provide the same if not better results than traditional methods of surveying and they are cheaper and more efficient.