LIDAR and photogrammetry
Lidar and photogrammetry are two methods of mapping topography and producing 3D models such as digital surface models (DSMs), digital terrain models (DTMs), a point cloud or a textured 3D mesh. The two approaches are complementary and suitable for different uses. Which one you choose therefore depends on your project, the terrain and your expectations in terms of deliverables.
Lidar (LIght Detection and Ranging) is an active remote sensing technology based on a laser scanner. The scanner emits a light beam towards the ground and the reflected ray is captured and analysed. The return time enables the distance of the object from the sensor to be calculated and, combined with the recording of the scanner’s path, this information makes it possible to locate the point precisely in space. This procedure is repeated millions of times over, allowing the terrain to modelized in 3D by a point cloud.
The crucial advantage of this technology is that it allows the topography to be mapped even beneath vegetation. The emitted rays are able to pass through gaps in the canopy to reach objects and the ground.
Lidar is also relevant for mapping narrow objects, such as power lines.
L’Avion Jaune has special expertise in the use of drone lidar technology for mapping topography. In 2013, as part of its R&D work, our team developed the first lidar sensor for drones. Although these instruments are now marketed by our sister company and partly-owned subsidiary YellowScan, the two companies work together and L’Avion Jaune takes advantage of the latest technical improvements to offer you 3D models of the highest quality.
Photogrammetry is a passive technology based on the principle of stereoscopy. It allows you to reconstruct a 3D model from images taken from different points of view. It requires taking a series of broadly overlapping photos.
The advantage of photogrammetry is that it can be used with aerial images taken by a drone or plane, meaning it can be used for surface area, resolution and precision at all scales. Extensive areas or difficult-to-access zones are best covered by plane. If done by a drone, it allows objects to be studied at resolutions down to the millimetric scale.
Its principal advantage is that it can be used to generate 3D colour models of the terrain (colorization of the point cloud, texturization of the 3D cloud, overlaying orthophotos onto elevation models, etc.)
L’Avion Jaune has solid experience of photogrammetry. It has used this technique for more than ten years to produce high-quality DSMs, DTMs and orthophoto maps for a variety of applications, including agriculture, environment and urban planning. We have the capability to implement various sensors and vectors, which enables us to choose the best solution for the task in hand. L’Avion Jaune is expert in a wide variety of photogrammetric software programmes and we develop our own tools to respond as best as possible to our customers’ needs.