Drone LiDAR vs Photogrammetry: Which Is Right For Your Survey?
Drone LiDAR vs photogrammetry is one of the most common questions we’re asked when planning aerial surveys. Both methods capture accurate 3D data from the air, both produce point clouds, terrain models and survey drawings, and both can be flown from the same drone platform. The difference lies in how they collect that data, and that difference decides which one will give you the most reliable result on your site.
At Merrett Survey Limited, we have been surveying for more than 40 years and have flown both methods on projects across the UK and overseas. In this guide we explain how each technique works, where each one performs best, and how we decide which to recommend, so you can go into your next project knowing what to ask for.
What is the difference between LiDAR and photogrammetry?
Photogrammetry builds a 3D model from photographs. The drone flies a planned grid over the site, taking hundreds or thousands of overlapping high-resolution images. Specialist software then matches the same points across neighbouring photos and calculates their position in three dimensions, producing a dense point cloud, an orthomosaic (a single, scaled aerial image of the whole site) and a digital surface model.
LiDAR (Light Detection and Ranging) measures distance directly. The sensor fires hundreds of thousands of laser pulses per second and records how long each one takes to return, combining this with precise GNSS positioning and an inertial measurement unit to place every point in space. Because a single pulse can return several times as it passes through gaps in leaves and branches, LiDAR can record the ground surface beneath vegetation as well as the canopy above it.
In short, photogrammetry sees what a camera sees, while LiDAR measures what a laser can reach. That one distinction drives most of the practical differences below.
Is LiDAR more accurate than photogrammetry?
Not necessarily. On open, well-lit ground, both methods can deliver survey-grade results when they are flown and processed correctly. Accuracy depends far more on how the survey is carried out than on the sensor alone: flight height, image overlap or point density, the quality of GNSS positioning, and the use of ground control points to tie the data to a known coordinate system and check it independently.
Our drones use RTK GPS, backed by a GNSS base station and surveyed ground control and check points. For a typical topographic survey, this gives photogrammetric data accurate to approximately 2cm, and closer still on detailed work such as building facades. We explain the factors behind these figures in more depth in our article Is A Drone Survey Accurate?
Where LiDAR pulls ahead is reliability in conditions that defeat a camera. Under trees, scrub or crops, photogrammetry can only map the top of the vegetation, so the ground beneath is estimated or missing altogether. LiDAR records the true ground surface through gaps in the canopy, which makes it the more dependable choice wherever ground levels matter and the site is not clear.
Drone LiDAR vs photogrammetry: which should you choose?
The right method depends on your site, the deliverables you need and how the data will be used. These are the factors we weigh up with clients at the planning stage.
Sites with trees, hedgerows or dense vegetation
Woodland, overgrown land, riverbanks and embankments are where LiDAR earns its place. Recording the ground through foliage avoids the need for slow and sometimes hazardous ground-based surveying across difficult terrain, and gives designers a terrain model they can trust for drainage, earthworks and flood risk assessment.
Open sites and visual deliverables
On clear land, construction sites, quarries and stockpiles, photogrammetry is highly effective. It produces sharp, true-colour orthomosaics that are easy for the whole project team to read, alongside accurate surface models for volume calculations and progress monitoring. It is also well suited to very large areas where high-resolution imagery is a key output.
Structures, power lines and fine detail
Thin features such as cables, pylons, railings and narrow structural members are difficult for photogrammetry to reconstruct, because there is little texture for the software to match. LiDAR captures them directly as points, which is one reason it is widely used for power line and infrastructure corridor surveys.
When combining both methods makes sense
Many projects benefit from both. Modern drone LiDAR sensors carry an RGB camera, so the laser data can be colourised for easier interpretation, and photogrammetry can add a high-resolution orthomosaic on top. Aerial data can also be combined with ground-based laser scanning to capture areas that are unsafe or impossible to reach on foot, such as the underside of a structure, producing one complete 3D dataset.
LiDAR and photogrammetry at a glance
| Consideration | Drone photogrammetry | Drone LiDAR |
|---|---|---|
| How it captures data | Overlapping photographs processed into 3D | Laser pulses measured directly |
| Ground under vegetation | Limited to the visible top surface | Records the ground through gaps in the canopy |
| Visual outputs | High-resolution, true-colour orthomosaics | Point clouds, colourised with an onboard camera |
| Thin features (cables, railings) | Often incomplete | Captured well |
| Lighting and surface | Needs good light and visible texture | Less affected by light; struggles on water and glass |
| Typical uses | Open sites, stockpiles, progress monitoring, large-area mapping | Woodland, embankments, corridors, flood modelling |
Our drone surveys in practice
Our team has flown drone surveys in a wide range of environments. In Greenland, we surveyed 25 square kilometres at a resolution of 2.5cm per pixel, using photogrammetry to produce point clouds, contours and Digital Terrain Models across terrain that would have taken many weeks to survey on foot. Closer to home, our commercial drone surveys support developers, engineers and asset owners with LiDAR and photogrammetry tailored to each site.
Every UK flight is planned in line with the Civil Aviation Authority’s rules for drone operators, taking account of airspace, permissions and any restrictions around the site before we fly.
Choosing the right aerial survey method
There is no single best method for every project. Photogrammetry is often the natural choice for open sites where clear imagery is valuable, while LiDAR is the more reliable option wherever vegetation, fine detail or true ground levels are critical. On many sites, the strongest result comes from combining the two, often alongside a conventional topographical survey on the ground.
If you are unsure which approach suits your site, get in touch with our team. We’re happy to talk through your project and advise on the best method, with no commitment.
Frequently asked questions
Can drone LiDAR see through trees?
LiDAR does not see through solid objects, but laser pulses pass through gaps between leaves and branches and return from the ground below. With enough point density, this gives an accurate ground surface even under fairly dense canopy. Very thick evergreen cover can still limit how many pulses reach the ground, which we assess when planning the flight.
What deliverables do I get from a drone survey?
Depending on the method and your requirements, deliverables can include point clouds, orthomosaics, Digital Terrain and Surface Models, contours and CAD drawings in formats such as DWG and DXF, ready to drop straight into your design workflow.
Is drone LiDAR or photogrammetry better for a quarry or stockpile survey?
For open quarries and stockpiles with little vegetation, photogrammetry usually gives excellent volume calculations alongside clear imagery for reporting. LiDAR becomes the better option where faces are partly vegetated or where very fine surface detail is needed.
Our dedicated LiDAR service, including aerial LiDAR sourcing, independent quality control and processing into terrain models and contours, is covered in more detail at lidar.co.uk.
Peter Merrett - Owner & CEO
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