Utility surveys are an important aspect of any site construction work. Most underground services can be detected using electromagnetic detection equipment which can normally determine depth and measurements for cables, metal pipes and drainage runs. Pre-construction site survey is one of the most important steps in the engineering and placement of a new optical cable. While there are several specific types of listings for power cables, specifically for tray. Optical surveys in geotechnical monitoring are used to monitor ground, guide wall, and slurry wall movements.