LiDAR or photogrammetry? How we choose the method
Both methods produce a 3D model from the air. The difference shows on the ground, under the trees.
How each one works
Photogrammetry computes the shape of the ground from many overlapping photographs. It gives a very detailed picture and an orthophoto map, but it sees only what is visible in the photographs. LiDAR sends out laser pulses and measures the time they take to return. Some of the pulses pass between the leaves and reach the ground.
| Photogrammetry | LiDAR | |
|---|---|---|
| Bare ground, settlements | Excellent | Very good |
| Ground under vegetation | Limited | Excellent |
| Thin structures, cables | Weak | Good |
| Orthophoto map | Yes, high resolution | With an accompanying camera |
| Flying in low light | No | Yes |
When we choose photogrammetry
For quarries, construction sites, settlements, coastlines and monuments, where the ground or the structure is clearly visible and you need a high-resolution orthophoto map.
When we choose LiDAR
For streams and vegetated slopes, forest land, linear infrastructure projects and anywhere the study needs the actual ground rather than the tops of the trees.
Combining the two
On most large projects we fly with both sensors: LiDAR gives the ground, photogrammetry gives the image. Our Matrice 400 carries both sensors, the Zenmuse P1 and the Zenmuse L2, so on the same site visit we fly with one and then with the other.