A drone survey involves utilizing an unmanned aerial vehicle (UAV), also known as a drone, to acquire aerial data utilizing sensors that are positioned facing downwards, including RGB or multispectral cameras, and LIDAR payloads. When using an RGB camera during a drone survey, photographs of the ground are taken from various perspectives, and each image is marked with coordinates.
A photogrammetry software can use the data to generate geo-referenced orthomosaics, elevation models, or 3D models of the project area. These maps enable the extraction of information, including precise distances or volumetric measurements.
Drones have an advantage over manned aircraft or satellite imagery as they can fly at lower altitudes, producing high-resolution and accurate data quickly. This approach is less expensive and not affected by atmospheric conditions like cloud cover.
What are the Benefits of Drone
Surveying?
Reduced Field Time and Costs
Using a drone for capturing topographic data is faster by up to five times compared to land-based methods and requires less manpower. By placing a few Ground Control Points (GCPs) and having the drone capture the data, this in turn saves valuable time. Consequently, survey results can be delivered more quickly and at a lower cost.
Provide accurate and exhaustive data
Total stations have the capability of measuring only individual points. However, a single drone flight has the potential of producing thousands of measurements that can be represented in various formats such as orthomosaic, point cloud, DTM, DSM, contour lines, and more. The 3D geo-data is embedded in each pixel of the resulting map or point of the 3D model.
Map otherwise inaccessible areas
With an aerial mapping drone, you can take off and fly almost anywhere, without being limited by unreachable areas, steep slopes, or harsh terrains that are unsuitable for traditional measuring tools. You no longer need to close down highways or train tracks, and there is no organizational overhead required for data capture during operation.
What are drones used for in
surveying?
Land Surveying/cartography
Survey drones have the ability to generate high-resolution orthomosaics and detailed 3D models of areas where low-quality, outdated, or non-existent data are available. This capability allows for the quick and easy production of high-accuracy cadastral maps, even in complex or difficult-to-access environments. Additionally, surveyors can extract features from the images, such as signs, curbs, road markers, fire hydrants, and drains.
After post-processing with a photogrammetry software, these same images can produce very detailed elevation models, contour lines and breaklines, as well as 3D reconstructions of land sites or buildings.
Land management and development
Aerial images taken by drones greatly accelerate and simplify topographic surveys for land management and planning. This holds true for site scouting, allotment planning and design, as well as final construction of roads, buildings and utilities.
The images captured by drones also serve as the basis for detailed site topography models, which are useful for pre-construction engineering studies. The data generated can be easily transferred to any CAD or BIM software, allowing engineers to promptly start working on a 3D model.
Since data collection by drones is highly repeatable and inexpensive, images can be taken at regular intervals and overlaid on the original blueprints. This process enables the assessment of whether the construction work is proceeding in accordance with the plan specifications.
Precise measurements and Stockpile Volumetric Measurements
High resolution orthophotos enable surveyors to perform highly-accurate distance and surface measurements. Using 3D mapping software, volumetric measurements can be obtained from the same images, providing a fast and cost-effective method for calculating stocks in mines and quarries for inventory or monitoring purposes.
With a drone, surveyors can capture significantly more topographic data points, resulting in more accurate volume measurements. This approach is also much safer than manually collecting data by climbing up and down a stockpile. As the data is collected from above, site operations can continue uninterrupted. Additionally, the short acquisition time allows for the capture of a site snapshot at a specific point in time.
Urban Planning
Using 3D mapping software, volumetric measurements can be obtained from the same images, providing a fast and cost-effective method for calculating stocks in mines and quarries for inventory or monitoring purposes.
With a drone, surveyors can capture significantly more topographic data points, resulting in more accurate volume measurements. This approach is also much safer than manually collecting data by climbing up and down a stockpile. As the data is collected from above, site operations can continue uninterrupted. Additionally, the short acquisition time allows for the capture of a site snapshot at a specific point in time.
Thanks to 3D models, buildings can also be easily overlayed onto their environment, giving planners and citizens an experimental perspective of a complex development project. 3D models also allow analysis and visualization of cast shadows and outlooks/views.
What kinds of deliverables can you
expect with drone surveying?
Orthomosaic Maps
Drone images are corrected for image distortion and stitched together during post-processing to create a highly-accurate orthomosaic map. Each pixel contains 2D geo-information (X, Y) and can directly procure accurate measurements, such as horizontal distances and surfaces.
File formats: geoTIFF (.tiff), .jpg, .png, Google tiles (.kml, .html)
Digital surface models (DSM)
Drone images can also be used to create DSM models of the area. Each pixel contains 2D information (X, Y) and the altitude (Z value) of the highest point for this position.
File formats: GeoTiff (.tif), .xyz, .las, .laz
Digital terrain model (DTM)
After filtering objects such as buildings, the drone images can be used to create DTMs with each pixel containing 2.5D information (X, Y, and Z value of the highest altitude).
File formats: GeoTiff (.tif)
3D textured mesh
The 3D textured mesh is a reproduction of the edges, faces, vertices and texture of the area shot by the drone. This model is most useful for visual inspection or for when external stakeholders or public involvement is essential for a project.
File formats: .ply, .fbx, .dxf, .obj, .pdf
Contour lines
Depending on the project requirements, either the DTM or DSM model, with custom contour intervals, can be used to create a contour lines map, giving you a better understanding of the surface of the area shot by the drone.
File formats: .shp, .dxf, .pdf
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