Pick The Solution For Your Needs
In drone survey missions, the choice between photogrammetry (top image) and LiDAR (bottom image) depends heavily on your mission and your budget.
Drone photogrammetry is when a drone captures a large number of high-resolution images over a specific area. You can use these images to reconstruct the terrain in 3D using image overlap and sufficient ground control.
Photogrammetry is best for mapping, surveys, mining, broad-coverage combined with high horizontal and vertical accuracy.
In contrast, LiDAR (which stands for light detection and ranging) is a remote sensing technology that uses rapid laser pulses to map out the surface of the earth.
LiDAR is useful when used to create high-resolution digital surfaces, terrain and elevation models used for various business applications.
Both photogrammetry and LIDAR can provide remarkable levels of 3D model accuracy, especially compared with terrestrial sampling methods.
A big advantage of photogrammetry is that this technique not only generates accurate 3D models, but also full-colour, high-resolution information for every point on that model, giving clear visual context.
This makes interpretation and analysis of the results much easier compared to a pure LiDAR point cloud.
However, when it comes to surveying land with dense vegetation, where the light pulses can still penetrate between branches and leaves, LiDAR gets highly-detailed information.
This is a big advantage over photogrammetry, as photogrammetry can only produce accurate surveys when there is sparse vegetation on site. While LiDAR does have similar limitations, under good conditions it can penetrate areas with up to 90% vegetation. (Photogrammetry sits closer to the 60% mark).
LiDAR is also a better option for mapping narrow structures, such as power lines and railway tracks, and it can capture data in poor lighting conditions.
LiDAR gives you a point cloud, but because photogrammetry is stitching photos together to create your model, you get the visual details of every feature on your site. It means that photogrammetry is better suited for surveys which require visual data.
One of the biggest differences between photogrammetry and LiDAR is the price.
Thanks to innovation, LiDAR has become a much more accessible solution than it used to be. That said, it still comes at a price, and can be a more costly solution than photogrammetry.
In truth, both LiDAR and photogrammetry and powerful tools for aerial surveying and mapping. Both have their strengths and weaknesses. More often than not, it depends on which is best suited for the specific job in-hand.