Technology
No jargon required. LiDAR measures distance by timing light. Everything else — the models, the volumes, the millimetres of movement — is what you do with millions of those measurements once you have them.
The dataset
Picture millions of tiny dots, each one marking an exact point in space where a laser pulse struck a real surface. Together they form a detailed virtual replica of a building, a landscape or an object — accurate enough to measure against.
That replica can be measured remotely, checked for change between visits, and used to plan renovation or construction without anyone returning to site. Every point also carries extra information: how strongly it reflected (intensity), and often its true colour.
The practical consequence: a question you had not thought of during the survey is still answerable afterwards, because the data was captured whether or not anyone asked for it.
The process
Many laser beams fire at once, not one. The whole sensor head also rotates on a second axis, so the beams sweep a near-spherical volume around it rather than tracing a single flat plane.
Each pulse reflects from the first surface it meets. Some pass through gaps in foliage and return from deeper, which is why a single scan can see both canopy and ground.
The time between emission and return gives distance, to within millimetres. Return strength is recorded too — that is the intensity value.
The sensor works out where it is from the scan data itself, matching each sweep against the ones before it — a technique called SLAM. No satellite fix is required, which is what makes indoors, underground and dense canopy practical rather than impossible.
Individual passes are aligned into one consistent cloud and, where absolute position matters, tied to surveyed ground control — so the result is georeferenced to the national grid rather than merely self-consistent.
Points are sorted into ground, vegetation, buildings and noise. This is where a raw cloud becomes a dataset you can extract surfaces and volumes from.
The instrument
Most people picture a single laser tracing one line, and a great deal of survey LiDAR still works exactly that way. The distinction matters more than it sounds, because it decides what a survey can and cannot reach.
Why this matters to you rather than to us. Coverage is complete in a single pass, so there are fewer setups and less time on your site. Places satellite positioning cannot reach — inside buildings, covered sheds, tunnels, beneath closed canopy, between tall structures — are ordinary jobs rather than special cases. And because the same sensor can be carried, driven or flown, a site with an indoor half and an outdoor half is one survey producing one dataset, not two surveys stitched together afterwards and hoped for the best.
Capture platforms
Each platform has a shape of site it suits and a shape it does not. Being straight about the limits is how you avoid paying for a survey that comes back with holes in it.
Best for: Interiors, covered sheds, quaysides, dense sites
A scanner carried at walking pace, building its own position from the scan data rather than from satellites. This is what makes indoor and covered capture possible, and it works around live operations without closing a site.
Range is shorter than airborne capture, so very large open sites take longer.
Best for: Roads, corridors, estates, port yards
The same principle at driving speed. Kilometres of corridor captured in a single pass, with the sensor high enough to see over kerbs, barriers and parked vehicles.
Only captures what is visible from the carriageway — it cannot see behind a solid boundary wall.
Best for: Open terrain, roofs, vegetation, large areas
Elevated capture covering ground that would take days to walk. The nadir and oblique angles reach roofs, embankments and canopy that no ground-based platform can see.
Weather and airspace dependent, and needs sky visibility — so not an option under cover.
Best for: Orthomosaics, textured models, visual condition
A 45 MP full-frame sensor with a mechanical global shutter, flown RTK. The global shutter is what keeps geometry true while the aircraft is moving — the difference between survey-grade and consumer aerial imagery.
Infers geometry rather than measuring it. Struggles under vegetation, on featureless or reflective surfaces, and in flat light.
A fair comparison
We operate both, so we have no reason to talk one of them up. LiDAR measures distance directly with laser pulses. Photogrammetry infers geometry by matching features across overlapping photographs — in our case from a 45 MP full-frame Zenmuse P1.
In practice we increasingly fly both on the same sortie and fuse the results — laser returns for the geometry you will measure against, P1 imagery for the colour, texture and orthomosaic you will actually show people. See aerial photogrammetry for what that produces.
Describe the site and the question. We will tell you which platform we would use, what it would capture, and where its limits would be.
