What is Drone Mapping?
The use of drones in mapping and surveying work is an established trend. It is increasingly common to see how surveyors support their reports on orthophotos, elevation maps, point clouds, and contour lines captured with UAVs and high-resolution cameras.
Drones and the software used to analyze aerial photographs undoubtedly enhance the performance of traditional surveying, but this does not mean that they are a substitute for traditional methods and techniques, but rather a complement that provides more accurate and higher quality information.
Drone surveying and photogrammetry, the enhancement of maps and plans by capturing aerial images, have become one of the most used techniques by surveyors when doing their work. After processing the photographs with specific software, areas, terrain profiles, distances, and volumes, letting the surveyor to create historical, comparative maps and share the information online with other people. A real treasure for professionals.
Advantages of drone mapping
These methods mean a great increase in productivity for companies that offer or require topographic services. Thousands of hectares can be reconstructed in a single working day with a drone and good software. This means a reduction of orders of magnitude in time and costs, while significantly increasing accuracy.
This technology has many other advantages:
- Productivity is increased while cost per hectare is considerably reduced.
- Time reduction in the execution of the work. In many cases, you will have access to the results on the same day of the flight.
- Centimeter accuracies are obtained in any part of the overflown area, not only in the points on which the assignment was centered.
- You have fine control over the level of accuracy of the results. When maximum accuracy is not required, it is possible to reduce the effort required in data capture and processing.
- Availability, without supplements or extra costs, of multiple results: orthophotos, elevation maps, point clouds, contour curves, and 3D reconstructions. Each professional decides which type of representation is the most appropriate.
- Unlimited access to precision measurement tools, online, without requiring expensive workstations or GIS/CAD software.
- Finally, avoids exposing workers to dangerous environments: busy roads, inaccessible areas, or steep terrain.
What is necessary to do a topographic survey with drones?
As in traditional surveying, there is a fieldwork component followed by subsequent office work. Each of the necessary steps is discussed below.
Execution of the flight
Fieldwork corresponds to the execution of the flight and the capture of supporting material.
Once the previous work is completed, and with the targets perfectly placed in the right location, it is time to execute the flight of the drone. To do this we must preload the mission in one of the flight planning applications available on the market. The choice between one application or another will depend mainly on the type of drone we use, its integrated controller, and the type of trajectory required.
The amount of overflown surface and the resolution of the final result determines the necessary flight time. Taking into account the capacity of the batteries, autonomy, and type of drone, several flights may be necessary. Compared to a fixed-wing drone a Multi-rotor drone battery can offer twice the time in the air and hundreds of hectares. As a rough estimate: a 20-30 minutes flight with a Multi-rotor drone and a single battery will allow cover tens of hectares.
Processing and analysis of results
During the flight, the drone will capture hundreds or thousands of images of the area we have flown over. In total, several gigabytes of data contain partial views of the terrain. These images do not provide much in themselves and need to be processed with photogrammetry software.
This is where ESRI ArcGIS software stands out, which is a complete system for collecting, organizing, managing, analyzing, sharing, and distributing geographic information. It is today the world’s leading platform for creating and using Geographic Information Systems (GIS) and is used by companies all over the world to make geographic knowledge available to government, business, science, education, and the media.
It should be thought of as a complete platform where anyone can work with and apply geographic information. Most people use maps to work with geographic information, but not just printed maps, interactive online maps allow you to understand the information, analysis tools, tasks, and workflows that people in your organization use to work more efficiently.