Aerotriangulation (AT) is the process of transferring ground control values (usually obtained in the field by surveyors or through GIS/GPS systems) to points on a block of overlapping (stereo) photographs by determining the mathematical relationship between the photographs and known ground control points. This process will ensure that all data extracted from the imagery meets a predetermined accuracy.

The outcome of the triangulation process is a fixed mathematical relationship between the aerial camera coordinate system, the imagery coordinate system, and the ground coordinate system control.

Aerotriangulation verifies the accuracy of field-surveyed control and provides general economic advantages in large projects.

The block of photographs is obtained through the capture of aerial photography. Qasco operates its own aircraft for capturing aerial imagery. For more information on our air operations, visit the aerial photography section of our website.

What equipment does Qasco use for aerotriangulation?

Qasco utilizes "traditional" film diapositive aerotriangulation techniques as well as the latest in computer software. We use ORIMA Orientation Management software from Leica Geosystems, which is a modern, high productivity solution for softcopy orientation and triangulation. It enables the efficient processing of large image data set coordinates, ground control points and airborne GPS coordinates. The automatic blunder detection process minimises the need for costly re-measurements.

Other products that the photogrammetry department specialise in include:

> Digital Terrain Models (DTMs)
> Topographic Mapping
> Earthworks Volumes