Definition - What does Photogrammetry mean?
Photogrammetry is defined as the science of using photographs to take measurements of objects. The photogrammetry software uses photographs that are input into the system and gives the output in the form of a map, drawing or a 3D model.
Geotechnical investigation is an integral part of trenchless pipeline installation projects and requires details of topical as well as sub-surface features. Photogrammetry can be used to study areas that are not easily accessible by land.
Trenchlesspedia explains Photogrammetry
Photogrammetry uses the principle of triangulation. Photographs taken from at least two different locations can be used to develop "lines of sight" from each camera. These lines are then mathematically intersected to produce co-ordinates, features, area or volume.
Photogrammetry is of three types namely:
- Aerial photogrammetry.
- Terrestrial photogrammetry.
- Close-range photogrammetry.
For the geotechnical investigation of remote areas for a trenchless pipeline project, aerial photogrammetry can be used. Aerial photogrammetry is carried out by mounting a camera on an aircraft and pointing the camera vertically toward the ground. As the aircraft passes over the target area, multiple shots are taken and later processed.
With advanced technology, now it is possible to conduct the operation using drones or unmanned aerial vehicles (UAV's).