LiDAR vs. photogrammetry: which method fits your site?

TechTalk

Both methods turn site conditions into measurable 3D data, but they capture it differently. LiDAR measures distances using laser pulses, while photogrammetry builds 3D models from overlapping photos. The right choice depends on your site conditions, the detail and accuracy you need, and how you plan to use the results.

See the full talk.

German episode

What is photogrammetry?

Photogrammetry creates measurable 3D data from overlapping photographs.

Images are taken from different viewpoints. Processing software identifies matching features across the images and calculates their positions in 3D to reconstruct the captured surfaces.

Depending on the capture method and processing settings, the results can include:

- A 3D point cloud
- A textured 3D mesh
- A terrain or surface model
- An orthomosaic: a geometrically corrected map image created from overlapping aerial photos

Construction teams use these outputs to document site conditions, measure stockpile volumes, track progress, and prepare as-built records. Photos can be captured with a drone or a handheld device such as SDX-PocketScan.

When photogrammetry works well.

Photogrammetry is a strong option when the surfaces you want to measure are clearly visible and contain enough visual detail for the software to match them across images. Think exposed earth, stockpiles, and open construction areas.

It also provides valuable visual context. Teams can see the site in photographic detail, making it easier to interpret measurements and communicate changes.

What to watch out for.

Good results start before processing.

Image overlap, flight height, camera settings, lighting, and sharpness all affect the quality of the reconstruction. Missing coverage or blurred images cannot simply be fixed by choosing different processing software.

Photogrammetry also reconstructs what the camera can see. If dense vegetation hides the ground, the photographs do not contain the information needed to directly reconstruct that hidden surface.

What is LiDAR?

LiDAR stands for Light Detection and Ranging.

A LiDAR sensor emits laser pulses and measures their returns to determine distances. Combined with positioning and orientation data, those measurements form a 3D point cloud.

Unlike photogrammetry, which derives geometry from matching photographs, LiDAR captures distances directly.

LiDAR sensors are used on different platforms, including drones, vehicles, machines, and handheld devices. However, sharing the same measurement principle does not mean every sensor offers the same performance.

Can LiDAR capture ground beneath vegetation?

LiDAR can sometimes capture ground points through gaps between leaves and branches. With suitable survey coverage and processing, these points can help create a terrain model beneath vegetation.

It does not see through solid leaves or branches. Ground coverage depends on vegetation density, viewing angle, sensor capabilities, and survey setup. Dense grass and low ground cover can still prevent the laser from reaching the terrain.

Ground classification also requires suitable software and review; it is not an automatic capability of every LiDAR system.

Which method should you choose?

Both LiDAR and photogrammetry can support stockpile measurement, earthwork surveys, and site documentation. Choose based on site conditions, capture frequency, required accuracy, and how quickly you need usable data, not the sensor alone.

Photogrammetry provides detailed photographic context. LiDAR measures surfaces directly and can support processing during capture. For ground beneath vegetation, assess whether the specific system and survey setup can capture enough ground points.

With either method, reliable measurements depend on positioning, coverage, processing, and independent checks.

Why Sodex systems use LiDAR.

Sodex’s machine-mounted scanning systems use LiDAR because direct distance measurements let us process 3D data in real-time as it is captured, without first reconstructing geometry from photographs. This supports continuous terrain capture while machines work. The reason is processing speed and automation, not seeing through materials.

Real-time processing during capture is separate from when results become available in SDX-Cloud, which depends on upload and cloud processing.

See SDX-Cloud with your own data.

Book a free demo and get 30 days of free access with your site processed at no cost.

Book a free demo

FAQs

No. LiDAR can offer important advantages for certain conditions, particularly when capturing ground points through gaps in vegetation. Photogrammetry can be a strong choice for visible surfaces and detailed photographic documentation.

News & Updates

Sign up for updates in construction tech, products, and industry insights.