The advent of non-military UAVs (unmanned aerial vehicles) or drones for consumer and commercial use (approx. 2010) has led to a surge in interest in aerial photography.

Placing a camera on a drone naturally led to drone-based photogrammetry - getting measurements and maps from photos taken by a drone.

Drones can be fixed wing or rotor. Typical rotor drones are multi-rotor (that is 4 or more propeller blades for stability). With the inclusion of height sensors, acceleration and tilt sensors, GPS for geo positioning, flight control software, gimballed camera mounts, and high quality cameras, modern drones are becoming very powerful mapping tools.

There are two styles of drone photography used in photogrammetry: nadir photography and convergent photography. Nadir means pointing straight down. The drone camera mount must be capable of pointing the camera lens straight down at the ground. A high-quality gimbal mount keeps the camera pointing that way even during turbulent flight. Convergent means the camera is at an angle to the ground.

Nadir photography projects are normally flown in grids. That is, the drone flies back and forth along a straight flight line, and alternating flight lines overlap. Like flying a grid. You end up with several images that overlap each other and cover the area of interest.

Convergent photography projects are often for mapping vertical faces (like cliffs), or for flight circles where the drone flies in an orbit around a point of interest. These photos must overlap as well.

The photogrammetry software will take the images (and potentially GPS position data, along with any camera information or calibration) from the drone and produce a set of 3D points or surfaces that describe the surface (the ground or object) being modeled.

The resulting data can be used for mapping, for volume measurements, for agricultural monitoring, etc. For high accuracy mapping, a combination of surveyed ground control points, and/or drone-based RTK or PPK GPS are used.

See who offers general purpose and uav photogrammetry software.