Drone LiDAR vs Photogrammetry: Which is more accurate?

When it comes to drone surveying, there are two options to consider: photogrammetry and drone LiDAR. Both methods have advantages and disadvantages, and understanding the nuanced differences between them is key to making the right choice for your application.

The pros and cons of drone photogrammetry

Photogrammetry is a fantastic option for bare earth imaging and identifying colors and textures. The aggregation of hundreds or thousands of photos results in a highly detailed orthomosaic that is incredibly valuable for a wide variety of applications.

Because photogrammetry uses a standard camera, rather than a specialized LiDAR module, it tends to be more cost effective than LiDAR.

There are two primary downsides to drone photogrammetry:

• Limited detail capture. Photogrammetry imaging can’t penetrate vegetation to capture data about the surface of the earth. Photogrammetry may also struggle to pick up narrow features such as power lines or curbs. If you’re surveying for these specific details or working in a wooded area, photogrammetry may not be your best option.
• Processing time. Even the best software may require up to 24 hours to process and aggregate all your images and data into a point clouds, orthomosaics, or other deliverables.

The pros and cons of drone LiDAR

While photogrammetry creates a composite based on multiple images, LiDAR collects direct measurements via a pulsed laser. LiDAR can penetrate dense vegetation to gather data about the surface of the earth. This is invaluable for surveying land that hasn’t been cleared to prepare for bidding, design, and construction. Plus, LiDAR is a superior choice for surveying fine details, such as power lines and curbs.

LiDAR offers advantages in post-processing as well. In general, the turnaround time on a final LiDAR product is one to one: If all the points were gathered in a twenty-minute flight, your software will only need about twenty minutes to generate the colorized point cloud.

The primary drawback to lidar is cost. There is a newly released LiDAR, the DJI Zenmuse L2, that lowers the cost of a quality LiDAR setup to $12,430.  The next jump in LiDAR quality brings you to something like the RESEPI Hesai XT32 for $32,990.  And for something with highest level of system accuracy of 1-2 cm, the RESEPI Teledyne-CL360HD comes in at ~$150k.

Which is more accurate: lidar or photogrammetry?

Lidar is more accurate than photogrammetry. But that doesn’t mean lidar is always the best option for a given project. As outlined above, photogrammetry offers plenty of advantages and is an excellent—and cost effective—surveying option for many projects.

We conducted and wrote a case study on lidar accuracy using the RESEPI Hesai XT32 lidar module, an EMLID Reach RS2+ base station, and a DJI Matrice 350 RTK drone. See the data here >

You can also download raw data from a surveying flight conducted with the DJI Zenmuse L1 and a DJI M300 RTK drone.