U.S. Bureau of Reclamation Digital Photogrammetry Research Report

Based on this completed phase of the research program, the Bureau of Reclamation (Reclamation) now has the capability to use digital photographs to map geologic discontinuities at dam sites. Several computer software programs and digital cameras were evaluated. Software designed specifically for mapping geologic features was purchased from the Commonwealth Scientific Industrial and Research Organization (CSIRO) in Australia. The SiroVision software consists of two integrated components: Siro3D, which allows for the creation of a three-dimensional image; and SiroJoint, which allows users to measure mapped parameters defining discontinuities using 3D images. The selection of this particular software over several more robust programs available on the market was based on several variables, including cost, ability to map geologic features directly within the program, and ease of use. There are several software products on the market that may produce higher accuracy and may be more useful for other applications, but SiroVision was a logical first choice for geologic mapping because the product is much faster to learn and does not require additional software to produce stereonets to display discontinuity orientations. Coupled with a Nikon D100 digital camera, SiroVision was used to map the discontinuity orientations at three locations, including East Canyon Dam. Initial problems with accuracy and processing were reduced significantly following separate field measurements at test sites. This testing allowed corrections to the data acquisition process as more was learned about the sensitivity of the software to various camera parameters, such as tilt and convergence, and more was learned to improve computer processing. The research testing allowed many iterations of the data processing during this learning period, with accuracy improvements each time.