Drone survey & mapping

An orthomosaic, a point cloud and a terrain model of your site, built by photogrammetry from a low-altitude drone flight — measurable, georeferenced, and delivered with the numbers that say how far you can trust it.

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 photogrammetry gives you

Several hundred to several thousand overlapping photographs are taken over the site. Reconstruction software finds the same physical points across many frames, recovers where each photograph was taken from, and from that geometry builds a 3D model of the ground. The photographs are then reprojected onto that model, so that the resulting image has the lens and terrain distortion removed and one map distance means the same thing everywhere in it.

The practical difference from an aerial photograph: you can measure on it.

Typical work

What you receive

OrthomosaicGeoreferenced GeoTIFF (cloud-optimised on request). Typically 2–5 cm/px; a lower flight buys detail at the cost of area covered per flight.
Point cloudLAZ for your surveyor or GIS, plus a web-streamable copy so the model opens in a browser with no software to install.
Terrain & surface modelDSM/DTM raster plus contours, in NAP heights — delivered when the dense reconstruction supports them and they survive an independent check.
3D meshTextured OBJ or GLB on request, for visualisation and design context.
VectorsTraced features — edges, paths, boundaries, observations — as GeoJSON or GeoPackage on request.
Private web viewerA password-protected page for the project: pan and zoom the survey, switch the photo against the terrain, measure distance and area in the browser, and download every file from one place.
Quality reportImages captured and reconstructed, ground sample distance, reprojection error, GNSS residuals (CE90/LE90), reconstructed extent, and which checks were run.
Coordinate systemRD New (EPSG:28992) with NAP heights by default; WGS84/UTM or another CRS on request.

Accuracy, stated plainly

Relative accuracy — distances and areas within one flight are consistent to a few centimetres. It is bounded by ground sample distance and reprojection error, and both are published per delivery rather than assumed.

Absolute position — without ground control, georeferencing comes from the aircraft's own GNSS. That is metres, not centimetres: expect a few metres of absolute offset, quantified per delivery as CE90 (horizontal) and LE90 (vertical). For most site work this is irrelevant, because the question is how far it is from A to B, not where A sits on the globe. Where it does matter, it has to be fixed properly.

Ground control — surveyed markers (GCPs) placed and measured before the flight, plus at least one tape-measured baseline in view of the camera, tie the model to real-world coordinates and give an independent check on scale. Laid on request; the extra field time is small next to what it settles.

Heights — height is the first thing photogrammetry gets wrong. A block flown without crossing lines or without ground control can bend into a dome while every internal check still looks clean. So heights are published only when the dense reconstruction supports them and they check out against AHN. Where that check fails, no contours, no profiles and no volumes are issued, and the delivery says why.

A survey that cannot be checked is not a survey. Where a result is corroborated by indirect evidence rather than proven by measurement, the delivery states which of the two it is, and on what evidence — in those words.

How a project runs

  1. Scope. Site, area, what has to be measurable, target resolution, coordinate system, and whether ground control is needed.
  2. Flight. Height and overlap planned for the target resolution — nadir grid, crosshatch, or oblique where façades and steep faces matter. VLOS, daytime, within EASA and local restrictions.
  3. Processing. Reconstruction, then quality control: reprojection error, GNSS residuals, and a horizontal comparison against public reference data (PDOK/AHN) where coverage allows.
  4. Delivery. Private viewer plus the raw files. Typically within five working days of the flight; large or multi-block sites take longer, and that is agreed up front.

Operating framework

Full details: flight safety and regulations.

For visual inspection work — dikes, roofs, façades, infrastructure — see inspection & documentation.

Request

Include the site, roughly the area in hectares, and what has to be measurable:

contact@vhaelum.com