Insights — Technology
LiDAR vs photogrammetry: choosing the right technology.
Every reality capture project faces the same early question: laser scanning, photogrammetry, or both? The honest answer is that neither is “better” — they measure the world in fundamentally different ways, and the right choice follows from what you need the data to do.
How they work
LiDAR (Light Detection and Ranging) measures distance directly: a laser pulse leaves the instrument, reflects off a surface, and the return time gives a range. Repeated up to a million times per second, this builds a dense, dimensionally reliable point cloud. It is an active technique — it brings its own light, so it works in darkness and does not depend on surface texture.
Photogrammetry reconstructs geometry from overlapping photographs: software identifies common features across images and triangulates their positions. It is a passive technique — it needs good light and visual texture — but because it starts from photographs, its outputs carry true colour and photographic realism that LiDAR alone cannot match.
Accuracy
Terrestrial laser scanning is the accuracy benchmark: millimetre-grade measurement, independent of lighting, consistent across featureless surfaces such as plain walls, glass-adjacent interiors and plant rooms. Aerial LiDAR delivers survey-grade terrain data even through vegetation gaps, which photogrammetry struggles with because it can only model what the camera can see.
Photogrammetry’s accuracy is more conditional — it depends on image quality, overlap, camera calibration and ground control. Well-flown UAV photogrammetry with proper ground control points routinely achieves centimetre-grade results across large open sites, which is ample for most planning, volumetric and monitoring work.
Cost and speed
Photogrammetry generally wins on capture economics for large open areas: a UAV with a good camera covers ground quickly — multi-square-kilometre coverage in a day is realistic — and the sensor cost is a fraction of a LiDAR payload. LiDAR carries higher equipment cost but needs less favourable conditions and less post-processing interpretation to yield reliable dimensions, which matters when the deliverable is a measured drawing rather than a visual model.
Where each wins
- Choose LiDAR for measured building surveys and scan-to-BIM, interiors and plant rooms, low-light or confined environments, terrain under vegetation, and anywhere dimensional certainty is the point of the exercise.
- Choose photogrammetry for large open sites and stockpile volumetrics, visually rich deliverables — textured meshes, orthomosaics, virtual tours — condition records where photographic evidence matters, and repeat monitoring flights where cost per capture counts.
The real answer is usually both
In practice, most of our projects fuse the two. A typical integrated capture pairs aerial photogrammetry for site-wide context and visual fidelity with terrestrial LiDAR for dimensional control around structures — merged into a single geo-referenced dataset. Our Worcester industrial yard programme is a working example: UAV topographical survey plus terrestrial scanning, producing a photorealistic 3D model and as-built CAD drawings from one campaign.
The technology question, in other words, is really a requirements question: what decisions will this data support, to what tolerance, in what format? Answer that, and the sensor mix chooses itself. If you would like help answering it for your site, that is exactly what our consultation stage is for.