Model the world in 3D with drones
High Quality Deliverables
A 3D drone mapping is essentially a land survey, but completed much faster, safer and cost-effective when compared to using traditional techniques. 3D drone mappings can be completed for terrains, roofs, earth material stockpiles, and operational or maintenance tasks. The deliverables include 3D point cloud, 3D mesh, 3D CAD drawings, 2D orthomosaic and volumetric measurements. These deliverables are provided in a large variety of file formats that can be accessed by most survey software applications.
There are several technologies that deliver the best results for 3D drone mappings of land surveys. Drones can use laser sensors as well as high resolution cameras. The laser sensor is known as LiDAR. The high resolution camera system is called photogrammetry. Both have their pros and cons and the choice depends on the project requirements.
Photogrammetry is as old as the camera itself and used for topographic surveys as early as the 1850’s. Photogrammetry uses photographs to extract 3-dimensional measurements from 2-dimensional pictures. Today’s modern high-resolution cameras are small enough to be mounted on small drones which are subject to less restrictions than larger drones based on take-off weight. Yet with HD cameras powerful enough to take 40 megapixel pictures, the resolution provides enough data to generate a 3D terrain mapping accurate to within 1cm.
LiDAR is sometimes also referred to as "LIDAR", "LIDaR", "Lidar" as well as 3D Laser Scanning. The term refers to Light, Detection and Ranging. The technology uses a fine laser that emits pulses of ultraviolet, visible, or near infrared light to objects and uses a special sensor to detect the reflected energy. LiDAR is extremely accurate and when completed by a surveyor at ground level or by a drone at low altitudes, the accuracy can be sub-centimeter. LiDAR maps that were created using airplanes at higher altitudes are less accurate and not useful for most projects.
LiDAR vs Photogrammetry
There are a significant number of articles debating this topic online and it really comes down to the use case. Overall, the equipment is far more expensive which can increase project costs.
Based on our experience at Inflights, photogrammetry works well when:
- roofs and buildings
- low density of vegetation
- precision of 1-3cm is enough
- color value of the terrain / building needs to be used
LIDAR is good when:
- high density of vegetation (forest, agriculture fields)
- resolution of sub cm is required
Inflights has developed a proprietary method to be able to use photogrammetry also for areas where there is some vegetation like trees. Using advanced technology the experienced engineers are able to model the terrain under trees with reasonable accuracy.
Important to note is that recent advancements in LiDAR technology are continuously reducing the size and cost of equipment.
Output of Surveys
In either case, the data that LiDAR and Photogrammetry produce is then converted into a 3-dimensional image. In the case of land surveys, a 3D point cloud model of a landscape is the main output. Other deliverables include a texture mesh, orthomosaic, and digital surface models. LiDAR has the extra output of multispectral images that are ideal for agriculture and measuring in low-light environments.