Drone inspection & site documentation
Low-altitude aerial capture of assets that are awkward, slow or unsafe to walk — delivered as a map you can search, with every observation pinned to its coordinate and its source photograph attached.
Operating from Waalwijk across the Netherlands. Registered as a drone operator with the RDW, flying in the EU A1 Open category with a sub-249g aircraft.
What gets inspected
- Dikes, banks and water defences — crest and slope condition, cover breaks, erosion, animal burrows, seepage traces at the toe.
- Roofs — flat and pitched, including detail no one wants to put a ladder against: flashing, membrane seams, ponding, blocked outlets.
- Façades and structures — captured obliquely rather than straight down, where the surface of interest is vertical.
- Solar fields — layout, soiling, damaged or displaced panels, vegetation encroachment.
- Yards, sites and infrastructure — condition and change over time, flown to the same plan so two dates compare honestly.
How the delivery is put together
The flight produces an orthomosaic of the asset — the same photogrammetric base as a survey delivery — plus the individual frames at full resolution. Observations are marked on the frames, and each one carries the coordinate it was taken at, so a second person can go and stand on the spot.
In the viewer you get the map, the pins, and the source photograph behind each pin, side by side. In the file set you get the orthomosaic, the marked and unmarked frames, and the observation list as GeoJSON if you want it in your own system.
What you receive
| Orthomosaic | Georeferenced GeoTIFF of the inspected asset, typically 1–5 cm/px depending on flight height. |
|---|---|
| Frames | Full-resolution photographs, marked and unmarked, for every observation. |
| Observation list | Numbered, with coordinates, what was seen, and how confident that reading is. GeoJSON on request. |
| Private web viewer | A password-protected page for the project: pins on the map, the source frame per pin, in-browser measurement, and every file downloadable from one place. |
| Capture record | Date, time, flight height, camera, images captured and reconstructed, ground sample distance, GNSS residuals, and the sun position at capture. |
What aerial inspection can and cannot see
Position is approximate at the metre level. Observation coordinates come from the aircraft's GNSS at the moment of capture — the position of the camera, not of the feature. At low nadir altitude the two agree to within about a metre in plan, on top of the absolute GNSS offset. Coordinates take you to the right few metres of a dike, not to a marked point on the ground.
Low sun is the tool. Surface texture — a rut, a crack, a slumped patch — shows up because it casts a shadow. A flight in flat midday light can render the same defect invisible. Capture is therefore timed for a low sun angle, and the sun elevation at capture is published with the delivery so you can judge for yourself what the light could and could not reveal.
Nadir imagery has limits. Fine linear features such as hairline cracks, and anything on a vertical face, are not reliably detected from straight-down imagery at survey altitude. Where those are the target, the flight is planned differently: lower, oblique, and slower. Detection is never claimed to be exhaustive — this is documentation that directs an inspection, not a substitute for one.
Findings are observations, not a verdict. Reports describe what is visible in the imagery. Assessment of structural or hydraulic significance belongs to your engineer or asset manager; the delivery is built to hand over to them intact.
Repeat flights are flown to the same plan — same height, same overlap, same line spacing — so that a later capture is comparable with an earlier one. Change detection only means something when the two captures are alike.
Operating framework
- Registered with the RDW as a drone operator.
- A1 Open category, sub-249g aircraft.
- VLOS, daytime only, maximum 120 m AGL; inspection flights typically run at 15–40 m.
- Flights are aligned with no-fly zones and local restrictions; site access and landowner permission are arranged with you.
Full details: flight safety and regulations.
For measurable outputs — orthomosaic, point cloud, terrain model, volumes — see survey & mapping.