Photogrammetry

Photogrammetry is the science of extracting accurate measurements from photographs. In dairy operations, it’s the technical foundation of drone-based silage volume measurement.

The basic process:

1. A drone flies over a pile in a structured grid pattern, taking photos with high overlap (typically 80% forward, 70% side).
2. Photogrammetry software identifies common features across overlapping images.
3. From those shared features, the software triangulates the 3D position of every point on the pile surface.
4. The result is a textured 3D model — point cloud, then mesh.
5. Volume is measured directly from the 3D model against a defined base plane.

Modern photogrammetry pipelines, when paired with surveyed Ground Control Points, produce volumetric measurements that hold up against ground-truth weights consistently within a few percent — accurate enough to drive operational decisions.

Photogrammetry has been around for a century in surveying. What changed in the last decade is that drones made aerial imagery cheap and accessible, and modern compute made the processing fast.