Accurate records of buried utilities are essential to ensure the integrity of underground infrastructure during construction, and to protect contractors and the general public from the consequences of utility strikes. Accurate and relevant as-built information from contractors can assist utilities and agencies in updating their records with new installations, as well as confirming the location of existing utilities. This paper discusses the utilization of photogrammetric methods to map existing and survey newly constructed utilities though a case study of a horizontal directional drilled utility installation in Mesa, Arizona. Photogrammetry is the science of utilizing two-dimensional photographic images to create accurate and scalable three-dimensional virtual models utilizing the principles of triangulation. Utilizing a series of photographs that capture the centerline of the borepath, site topography, survey benchmarks, paint marks from one-call services, and location of exposed utilities; then augmenting this with information pertaining to depth of the utilities and borepath from a log book, a model of the existing utilities and the new installation is created. This model can be exported into various formats for integration with the utility's record system. This method of as-built collection is superior to conventional practices as it locates the new installation in relation to the existing utilities, and allows agencies to confirm and update their records of all utilities in the project location. The method is as accurate as conventional survey and as-built record collection methods; but has a significantly reduced cost, increased productivity, utilizes commercial grade consumer electronics that the majority of contractors already own or can easily acquire, and does not require specialized training to perform.
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