What is LiDAR and when is it worth choosing over photogrammetry?

LiDAR (Light Detection and Ranging) measures distances using laser pulses. The sensor emits hundreds of thousands of pulses per second and calculates the distance to the point hit based on the time it takes for the reflected light to return. The result is immediately a point cloud – without the processing step required by photogrammetry.

The key difference: vegetation

Photogrammetry works from images. What the camera cannot see does not exist in the model – over a forest, you capture the tree crowns, not the ground beneath them. A laser pulse, by contrast, finds gaps in the foliage and reaches the ground. The same data can therefore be used to separate the surface model and terrain model (see DTM and DSM).

This is the main reason customers switch to LiDAR – not accuracy in itself.

When LiDAR is the right choice

• Vegetated terrain where the terrain model matters: forestry, embankments, renaturalised areas and landfills with vegetation.
• Narrow, tall structures such as overhead power lines, poles or railings – these are regularly fragmented in photogrammetry.
• Poor lighting conditions. LiDAR provides its own light and also works at dusk or in diffuse weather conditions.
• Low-texture surfaces: fresh snow, sand and uniform roof surfaces. Photogrammetry lacks matching points in these areas.

When photogrammetry is sufficient

For open, well-textured areas, photogrammetry delivers comparable accuracy – at a fraction of the hardware cost and with one genuine advantage: you also get a colour orthomosaic that you can show to customers. Construction site documentation, volume calculations on open stockpiles and roof surveys: LiDAR is rarely necessary for these applications.

In practice, many systems combine both – a laser scanner and a camera in a single payload, allowing the point cloud to be colourised.

What you need to plan for

LiDAR payloads cost several times as much as a camera and require a suitable carrier drone. There is also the post-processing effort: raw data must be combined with trajectory data, classified and filtered – this is a separate step requiring its own software and training. When you purchase LiDAR, you are not just buying a sensor, but a process.

Not sure which option to choose? We provide manufacturer-independent advice – book an appointment.