The following is a guest post by Dustin Price, Operations Manager at surveying company Landpoint.
Two technologies dominate modern surveying: LiDAR and photogrammetry. Both LiDAR and photogrammetry are used to create images and 3D scans of buildings and natural terrain, often in conjunction with advanced drone technology. But which is better for your survey project: LiDAR or photogrammetry?
LiDAR: An Advanced Technology Ideal for Maximum Accuracy
LiDAR surveys range in cost anywhere from a couple thousands of dollars to in the multi-millions of dollars, depending on the length and size of the survey. It can cost more than a traditional, photogrammetric survey, but it’s also more accurate. LiDAR is also a newer technology, using high precision lasers to create a 3D image of a landscape.
Ideal for complicated terrain: LiDAR can penetrate light cover, such as shrubbery, which lends it very well to surveys of overgrown or cluttered terrain. It’s also ideal for urban surveys, able to see through thin cover such as cloth, and around wires.
When paired with drones, LiDAR can quickly produce high-resolution, accurate scans. LiDAR technology itself is fast, and drones can produce high resolution images by carrying LiDAR technology close to the ground.
Use LiDAR for:
- Scans of overgrown areas. LiDAR can see through light shrubs, overgrown grass, and even shallow water.
- Scans in difficult-to-access areas. LiDAR is a high precision scanning tool that can be used with drone technology to create precise scans of areas otherwise inaccessible.
- Scans with a lot of detail. LiDAR is able to produce higher resolution, more accurate images compared to photogrammetry.
Related read: The best drone for carrying a LiDAR sensor
Photogrammetry: A Trusted Tool for Full-Color, Textured Imagery
Unlike LiDAR, photogrammetry produces full color, textured images. Photogrammetry creates images of land by using large numbers of photos, which are then composited together. These images are often more readable to the human eye than LiDAR images, even if they aren’t as versatile. Photogrammetric tools are often used for large plots of land, because the camera equipment tends to be significantly lighter than a LiDAR rig, extending platform flight time.
Photogrammetry does consume more in data: Rather than just mapping out points in the terrain, it’s creating large numbers of full-color images. Photogrammetry cannot see through brush, and it’s generally better suited for large-area surveys that don’t require much by way of fine, sub-inch precision detail.
Like LiDAR, photogrammetry can be combined with drone technology to produce surveys very quickly.
Use photogrammetry for:
- Scans that are easily read by the human eye. Photogrammetric scans look more like aerial photos than LiDAR images, making it easier for untrained eyes to identify land features.
- Scans of large plots of land. Photogrammetry can be paired with planes or helicopters to take quick surveys of extensive plots. Even with a drone platform, photogrammetry is better suited for larger scans, as its lighter weight gives drones longer flight time before needing to be recalled.
LiDAR vs. photogrammetry: How to Choose the Best Option for Your Survey
In general, LiDAR is best for smaller, more accurate surveys, while photogrammetry is best for large-scale, human-readable surveys. Landpoint, a land surveying company focusing primarily on the oil and gas industries, typically flies two primary drone platforms: the SenseFly eBee for long-distance surveys and the DJI Matrice 200 for more precision flights that need longer hovering times.
Both platforms can be outfitted with hundreds of options for sensors, but the more common go-to options for Landpoint are the MicaSense Rededge infrared camera, the Parrot Sequoia multispectral sensor, and the SenseFly S.O.D.A.
But in the debate of LiDAR vs. photogrammetry, there’s also a world where you may end up using both technologies combined over multiple flights to produce surveys that are the best of both worlds. This option is more expensive than either option alone, but may be worth it for high value or high-risk projects.
-By Dustin Price
Dustin Price is a licensed land surveyor and the Operations Manager at Landpoint. He leads the company’s technical approach to delivering professional surveying services by providing tailored solutions using UAV technology.