Geomatics techniques for structural surveying

Structural engineers may utilize geomatics techniques for precise and accurate measurements of discrete points, detailed facade recording, and the production of engineering drawings and plans. Techniques commonly used include direct measurement using a tape or gauge or, more recently, observations made from a reflectorless total station. Photogrammetric methods are also suitable for structural surveying. Terrestrial laser scanners have recently taken large steps in development and have the potential to become a useful survey tool. An overview of current recording techniques along with an introduction to laser scanning is given, followed by details of a test involving terrestrial survey, photogrammetry, and laser scanning at a site in the United Kingdom. Analysis of the results showed that measurement to targeted points using the laser scanner was comparable to measurement using traditional stereo photogrammetric methods, although care needs to be taken to reduce the impact of mixed pixels and multipath occurring within the scanned scene.