Drone photogrammetry is a measurement technique that enables 3D space to be modelled using 2D images acquired from a drone. By knowing the position and orientation of each image in space, a three-dimensional position can be calculated for each point of the terrain visible in several images, thus constructing a point cloud. This 3D reconstruction process is analogous to the way our brain interprets in three dimensions what our eyes perceive from different points of view. Uzufly’s processes make it possible to derive other products from the point cloud, such as a photorealistic 3D mesh, a digital surface model and an orthophoto.
Mobile mapping involves digitising the environment while moving along a route using various on-board sensors. The Orbis360 measurement system is made up of two high-performance laser scanners, a panoramic camera, planar cameras and various sensors to determine the precise trajectory followed. The only way to ensure high-quality geo-referencing of the various products is to calculate the trajectory correctly, since both the points measured by the scanners and the images are projected along this trajectory. As the scanners are equipped with laser scanners, the point cloud is obtained directly by LiDAR, an acronym for light detection and ranging. Georeferenced and oriented panoramic images are used as a visual aid.
✅ Generation of 3D data by overflight (no physical presence on site)
✅ Modélisation d’éléments non-visibles depuis le sol
✅ Modelling of elements not visible from the ground
❌ Possible flight bans over certain areas
❌ Modelling only of elements visible from the sky
✅ Fast acquisition (up to 300km in corridors and 100km in urban areas)
✅ Point cloud quality (fine elements, low noise, high density)
✅ Visual information via panoramic images and/or laser intensity, even at night
❌ Data only along the routes taken
❌ GNSS reception and direct georeferencing sometimes difficult (can be adjusted later)
Views of the point clouds in the centre of the village of St-Saphorin: the fine elements measured by the scanner (barriers, signs, street furniture) are often not reconstructed by dense correlation.
Views of the point clouds above the cantonal road: The edges of roofs are hidden areas for the drone. They cannot be determined cleanly and the points are interpolated there. On the other hand, roofs and roadside verges are not visible to the mobile system.
Roadside profile: point clouds obtained by dense correlation tend to smooth out salient features (example above with the kerb and guardrail). These same salient features, measured directly by mobile scanner, are rendered with high accuracy and low measurement noise.
The image above shows the extent of the point cloud acquired by drone (in blue) and that acquired by mobile mapping (in yellow).
The surface area covered by the drone makes it possible to generate large-scale, photorealistic and immersive renderings (the realism of the 3d model in the video above is particularly remarkable).
In the case of mobile mapping, the scope is limited to what is visible along the route taken. On the other hand, the panoramic images acquired are a very good way of visualising a location while immersing yourself in and moving around the desired street. What’s more, as the images are linked to the same trajectory as the point cloud, the latter can be superimposed on them (as in the illustration above, with the points coloured by their intensity). This makes it possible to take measurements (object sizes, surfaces, coordinates, etc.) directly while immersed in a panoramic image. These same measurements can also be made directly by navigating the point cloud in three dimensions. The publications at the bottom of this article allow you to test these different navigation and measurement modes.
Drone photogrammetry is useful for projects requiring a visual 3D representation of an area ranging from the size of a house to that of an entire town. It offers a wide range of applications such as integrating a construction project into its virtual environment, updating certain layers of land registry information, urban-scale simulations (for example: shadow simulations and solar potential estimation).
Mobile mapping is particularly well suited to mobility specialists, both in the road and rail sectors. The low measurement noise, accuracy of angles and fineness of digitised objects means that customers with particularly high requirements in terms of accuracy and measurement in the vicinity of roadways or railways can be satisfied. Panoramic images serve as a source of visual information by providing elements that can be interpreted by the human eye.
These two products complement each other by providing information where the other cannot. Mobile mapping ensures a high quality cloud near the road and the drone completes the model over the rest of the territory.
Regardless of the source and acquisition method used, 3d data can be distributed via web platforms.
Orbis360 and Uzufly offer you the possibility of distributing your own data to your customers via a customisable web viewer that requires no installation. The publications below allow you to try out different navigation modes for yourself. Don’t wait any longer and immerse yourself in a representation of the world around you!
