Because accuracy and reliability are essential for surveying professionals, it’s understandable that many have hesitated to adopt drone technology. Traditional methods work, and as the old saying goes, if it ain’t broke, don’t fix it.
But there are misconceptions driving this skepticism. Many surveying projects can be successfully completed with the accuracy drones provide. And while there is a precision tradeoff in some instances, there are tremendous cost, time, and safety savings to be made when integrating drones into traditional workflows.
Drones have become transformative tools in a range of industries. Surveying is no different, but traditional methods will always have a place. Indeed, in some cases, they represent the only possible solution.
Why are traditional surveyors switching to drones?
Time, cost savings, and safety improvements are the headline benefits that drones bring to a host of sectors. All three are already impacting the work of surveyors.
More and more professional payloads make all kinds of surveying available, such as professional drone cameras, Share 6100Pro, PSDK 102S, Share 202S Pro, Share 303S Pro specialized in photogrammetry, 3D mapping become much easier than ever before. LiDAR sensors L1 and so on.
Take the example of Huace, a data collection, and surveying service providing company in China. When comparing different methods during the survey of a stretch of railroad, the team discovered that the DJI Matrice 300 RTK and Share PSDK102S payload combined to reduce operation preparation time by two hours. This is because the built-in RTK module and PSDK102S sensor delivered enough metadata to effectively reduce the number of Ground Control Points (GCPs) required to zero.
On top of taking up valuable hours, these methods involve physically handling equipment on and close to the railway. It’s both a dangerous and a complex place to work. The introduction of drones into the equation meant fewer hours on-site, more automated processes, and less risk to surveyors - all without sacrificing the accuracy required. In fact, the Share 5 lens oblique cameras excelled despite low light conditions.
By reducing the number of GCPs required for surveying missions, sophisticated drones can save surveyors a huge amount of time. But it’s arguably in inaccessible or dangerous areas where the technology comes into its own. Train tracks are just one example of a working environment that’s far better suited to autonomous machines.
The final point to note is the depth of data that’s possible with drones. Despite needing a fraction of the manpower, a point cloud with millions of data points and, in many cases, greater detail, can be achieved in a reasonable turnaround time. To get the same output from classical methods would require significantly more time, instruments, and cost.
Which types of surveying projects are ideal for drones and traditional surveying tools?
Despite the benefits drones offer compared to traditional surveying methods, there are situations in which the old ways remain an important part of the equation.
The first thing to consider is the degree and type of accuracy that your project requires.
It’s here where the difference between relative accuracy and absolute accuracy is important. For many applications, relative accuracy - the accuracy of where objects are in relation to one another - is all that matters. The result of these projects can be reconstructed models such as 3D point clouds or orthomosaic maps. When the objects’ true positions on Earth are an important factor in the equation, a surveying process that provides absolute accuracy is necessary.
Taking a relative approach is a simple way to accurately assess volumes, distances, and height variations. But if that data is going to be combined with further informational layers, or if you are hoping to develop professional photogrammetric survey documentation, those measurements will need to be geographically oriented using Ground Control Points and/or supported by UAV Real-Time Kinematic (RTK) technology. RTK is a GPS correction solution built into drones that work with a ground station to accurately geotag images with GPS information as they are captured.
As a general rule, projects that require accuracy to within 2cm will need to be augmented by traditional methods. Drones consistently achieve 5cm accuracy, and depending on the payloads and flight parameters, up to ~1cm accuracy. If your project demands 2, 1, or even millimeter-level accuracy, traditional tools remain the best option.
Surveying projects where drones shine
Some environments and infrastructure are literally beyond the reach of traditional surveying techniques. But when data needs to be gathered - particularly at scale - drones are the ideal solution. Cell phone towers, solar farms, and treetop canopies are just a few examples of areas that can be mapped easily using drones.
Just because an area is within reach of ground-based surveying techniques, it doesn’t follow that it’s wise or safe to do so. Hazardous locations, including rooftops, ledges, roadways, unstable soil, steep embankments, and, as mentioned above, railway lines - all are dangerous places to work. Innovative drone solutions can carry out surveying tasks without risking teams on the ground.
When data depth matters
A significant benefit to aerial surveying is the depth and variety of potential outputs available. If you’re conducting an agricultural survey, multispectral sensors and high-definition cameras can gather the data you need to assess crop health and understand the situation in granular detail. If you’re carrying out a topological survey ahead of a construction project, LiDAR and photogrammetry enable 3D point clouds, orthomosaic maps, and high-density, digital terrain models, for a comprehensive overview. If you’re estimating stockpiles and looking for accurate volume measurements that aren’t hindered by human error, a few clicks of a drone’s camera can gather the information you need without putting staff in harm’s way.
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