Drone LiDAR vs. Photogrammetry

Which one is better?

The answer to that depends on a few different factors – what is your project, what is your end goal, what is your budget, what accuracy do you need?

Gila National Forest LiDAR Drone Point Cloud; lidar vs photogrammetry droneGila National Forest Photogrammetry Drone; lidar vs photogrammetry drone

Drone LiDAR

A LiDAR drone is a drone equipped with LiDAR technology. LiDAR is a remote sensing technique that stands for Light Detection and Ranging. It utilizes pulsed infrared laser beams to measure distances to the Earth’s surface. This information, along with information collected by the airborne system, can generate a 3D model the terrain. The LiDAR system does not provide photographic details, instead it creates a point cloud with the data that has been returned from the objects on the ground.

LiDAR technology is a relatively new technology, created in the 1960’s just after lasers were developed. It was used during the Apollo 15 mission in 1971, and then was used for commercial purposes in the 1980’s after GPS became available for public use.

These drones are used in a range of applications, such as surveying, topographical mapping, and creating 3D models of buildings and structures.

Are you considering buying a drone? Or contracting a drone survey service to fly your site? What if you could save on the cost of a drone or service? Before you make your decision, check out our data.

Drone Photogrammetry

Photogrammetry drones are drones equipped with photogrammetry software that captures and analyzes high-resolution aerial photographs to create 2D and 3D models. Drone photogrammetry is a two stage process. The first step is to capture the images required using a still or video camera mounted on a drone. Then the images need to be processed either manually or using photogrammetry software that combines the images into a single high-resolution orthomosaic aerial map. The software is able to correct distortions caused by the camera sensor or lens.

Photogrammetry has been used for over 100 years. It was even used during World War I to gather intelligence from behind enemy lines.

Drone photogrammetry is great for bare-earth mining and managing volumes and structures in civil construction.

Drone LiDAR vs. Photogrammetry

The main difference between LiDAR and photogrammetry drones is the type of imaging system used. A LiDAR drone uses a laser-based imaging system to capture data while a photogrammetry drone uses cameras to capture images. Both technologies are capable of producing excellent aerial mapping results; however, they differ in their price, accuracy, and applications.

LiDAR Photogrammetry
Accuracy Due to the nature of the LiDAR system, it has much higher relative and absolute accuracy. The accuracy is usually within centimeters. Absolute accuracy is harder to achieve with photogrammetry systems. Relative accuracy is fairly good with it being 1-3 times the ground sampling distance (distances between two pixels as measured on the ground). A lower ground sampling distance resulting in a clearer image and higher accuracy, but also means a higher processing time.
Coverage The swath width is generally wider. LiDAR is more effective at measuring and capturing small or narrow objects such as power cables, pipelines, and sharp-edge features. The swath width is generally narrower. Photogrammetry has a harder time capturing small or narrow objects such as power cables or pipelines.
Leaf Penetration LiDAR does not penetrate through leaves; however, it is able to penetrate the gaps between the leaves and branches to reach the ground. Photogrammetry cannot penetrate through leaves and the vegetation greatly reduces the accuracy of ground topography.
Limitations LiDAR data can be collected day or night; however, water absorbs near infrared light so it cannot penetrate clouds and does not operate as effectively during fog, rain, or snow. Photogrammetry is highly dependent on sunlight; and therefore cannot be carried out at night or on cloudy, overcast days.
Flight Overlap The flight overlap for LiDAR data is 20-30%, making acquisition time faster. The flight overlap for photogrammetry data is 60-90%, making acquisition time slower.
Complexity LiDAR is a fairly complex technology (although the theory behind it is quite simple), which requires a higher level of understanding, widening the margin error and increasing the demand for an experienced professional. Photogrammetry is a more straightforward surveying method that does not require an experienced professional to complete.
Processing Time Raw data takes a few minutes of calibration to create the final product. Raw data takes several hours to days to process. It takes on average 5-10 times longer than to process the data than to acquire it in the field.
File Format LAS/LAZ TIFF, PNG, JPEG, or BMP
Cost Due to the complexity of LiDAR, a drone based LiDAR system is much more expensive. Since a photogrammetry system is less complex, a drone based photogrammetry system is much cheaper.
Best Uses LiDAR is best for projects where accuracy and precision are crucial, you need to detect small or narrow structures such as cables, pipes, or telecom towers, or in areas where there is heavy vegetation. Photogrammetry is best for projects that require visual (photographic) data or for applications such as managing volumes and structure in mining and civil construction.

Conclusion

Drone LiDAR or photogrammetry, which is better? At the end of the day, it really depends on your application.

Do you have data from a drone? Are you looking to upload your data? Note: Equator accepts the following file formats: .zip / .shp / .prj / .dbf / .kml / .kmz / .las / .laz / .geojson.