From drone photos to a 3D model: photogrammetry in everyday work

Until a few years ago, surveying an area of several hectares was a matter of days with a total station. Today the same terrain is covered by one well-planned flight and a few hours of processing. Photogrammetry has not replaced geodesy, but it has moved most of the work from the field to the office.

How the model is built

The software finds common points between consecutive photos and, from the different camera positions, reconstructs the three-dimensional geometry. The result is a dense point cloud, from which the surface model, the orthophoto and the contours are derived. The main condition is overlap: photos with insufficient overlap produce empty areas that no setting can heal afterwards.

Accuracy depends on control points

The drone's GPS gives a position accurate to a few metres — enough for orientation, not for cadastral work. For centimetre accuracy you need ground control points measured with GNSS, distributed across the whole area and not only in the centre. The accuracy report with RMSE is not a formality: it is the document that shows whether the model can be used for official measurements or only for visualisation.

Where it delivers the most value

The clearest benefit is in monitoring works. By comparing two models from different dates, cut and fill volumes are calculated directly, without waiting for new topographic measurements. For difficult or dangerous areas — steep slopes, quarries, post-landslide zones — photogrammetry is often the only safe way to collect data.

How AlbGIS helps

• GeoMorph — our desktop application that processes drone photos into orthophotos, DSM/DTM, point clouds and 3D meshes, with processing that stays local.
• DEM to Contours — from the terrain model to contours, with DXF export ready for AutoCAD.
• Coordinate Transformation — conversion between WGS84, UTM 34N and local systems, essential before delivery.