Mapping underground infrastructure using photogrammetric methods

Underground infrastructure mapping in many urban areas lacks the necessary accuracy and detail required to conduct underground construction. This is a result of inadequate surveying methodologies and poor historical as-built records. One solution to this problem is the development of a mobile terrestrial photogrammetric mapping system to expose utilities on construction sites. This thesis outlines the design of the Underground Infrastructure Mapping System (UIMS). The system is comprised of three pieces of hardware including a tablet PC, a Global Positioning System (GPS) receiver, and a digital camera. Results indicte that the UIMS has an absolute spatial accuracy of 28 cm (within the City of Toronto) and a relative accuracy of 13 cm (95% confidence level). The data collection time per exposed utility feature is approximtely ten minutes on site, and an additional five minutes of post-processing. The cost of the system's hardware is under $5000.