The Photogrammetric Recording of Historic Transportation Sites

About the report:

The purpose of this study was to evaluate the applicability and accuracy of documentation drawings prepared from close-range me terrestrial photogrammetry and to compare them with the results of traditional documentation techniques which depend on hand measurements. The photogrammetric research was organized to coincide with equipment resources available within the Virginia Department of Highways and Transportation. The sites studied on a case-by-case basis illustrate types associated with transportation improvements that are likely be affected by federal requirements which demand documentation of certain historically significant sites. The variety of sites also demonstrates the adaptability and limitations of-the photogrammetric method. Documentation drawings executed by the photogrammetric method are presented in several stages of completion to illustrate the process. These drawings are considered successful documentation delineations, with certain limitations inherent in the process. The results of the photogrammetric technique were analyzed from two perspectives. A comparison was made between documentation drawings produced by the photogrammetric method and those made by the traditional hand measured method. An analysis also was made of the dimensional accuracy of the photogrammetric results by comparison with hand measurements taken at the, sites. A few photogrammetric models were studied to determine what additional types of dimensional information can be obtained from the stereoscopic models of these sites. The degree of accuracy, both dimensionally and in the representation of deteriorated areas, was found to be more than adequate for the demands of site documentation.

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