Photogrammetry vs LiDAR

Photogrammetry vs LiDAR

Photogrammetry

Drone photogrammetry uses images captured by a drone-mounted camera to reconstruct the terrain in an accurate 3D model using image overlap and sufficient ground control.

LIDAR

Lidar is a direct measurement where you physically hit a feature with light and measure the reflection.

Accuracy

Photogrammetry

In the case of photogrammetry, a quality, high-resolution, full-frame sensor camera can yield outputs with horizontal (x-y) accuracies in the range of 1 cm (0.4 in) and elevation (z) accuracies in the range of 2 to 3 cm (0.8 to 1.2 in) over hard surfaces, enabling precise volumetric analysis.

LiDAR

The typical absolute accuracy that you can expect from a lightweight LIDAR system on a fixed-wing drone at an elevation of about 100-200m is approximately 10 cm (4 in) horizontal and 5 cm (2 in) vertical.

By flying lower, lightweight UAV LIDAR provides a higher point density than manned aerial LIDAR and can achieve better accuracy even though the laser is less powerful.

Coverage

Both photogrammetry and lightweight UAV LIDAR rely on drones to capture the data. So in these cases, you can expect to cover up to 10 km2 (4 mi2) per flight. If you are working with classical airborne LIDAR, you can cover up to 1000 km2 (400 mi2).

Photorealisticity

Photogrammetry

Photogrammetry offers photorealistic mapping results in the form of orthomosaics, point clouds, and textured mesh. A true, life-like digital twin.

LiDAR

LIDAR offers a sparse laser point cloud that gives a general sense of shapes and contours but does not offer contextual detail. You can also colorize LIDAR data with RGB data, but this is a more complicated process.

Processing time

Photogrammetry

Photogrammetry processing for full resolution takes several hours (or days) depending on the project size. If you only need a sparse set of accurate tie points (like from a LIDAR source), photogrammetry tools offer downscaled processing options.

LiDAR

LIDAR point clouds are directly geo-referenced with real-time kinematic (RTK) positioning during flight.

Depending on the project size, the process takes from less than an hour (smaller projects with lightweight drone LIDAR) to several days (large projects with manned aerial LIDAR).

When to Choose LiDAR?

Choose LiDAR for:

• Mapping hard to access, complex, and overgrown terrain
• Capturing details on thin structures, such as power lines or roof edges
• Projects where detail and precision are the priorities
• When you're dealing with trees and vegetation.

When to Choose Photogrammetry?

Choose Photogrammetry for:?

• Context-rich scans that are accessible and require minimal post-processing and expertise
• Maps and models that are easy for untrained eyes to understand
• Datasets that need visual assessment

Conclusion

It’s not that one is necessarily better than the other. Ultimately it’s the task at hand that will determine the best solution.

If the contrast, lighting, subject, and conditions are in your favor, photogrammetry is probably more than adequate for the job. But for challenging mapping projects where elevation accuracy, complex structures, or partly shrouded terrain are involved, LiDAR is probably the way to go.

Cost can also be the deciding factor that pushes you in one direction or the other.

At GeoDrones we have the latest technology when it comes to Drone Photogrammetry and surveying. Our pilots are trained and certified.

With numerous successful projects backing our claims, our portfolio speaks for itself.

We've helped businesses reduce the running costs of their projects by about 50% and the running time by about 70%

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