COMPUTER IMAGING FOR TRANSPORTATION PROJECTS

Advances in the speed and processing power of personal computers in recent years have enabled design professionals to visually analyze transportation projects, both in three-dimensional models and photo-realistic images prior to their construction. This article reviews several techniques that were utilized successfully for the visual analysis component of an environmental impact statement for proposed improvements to the Guanella Pass Road. The 23-mi (37-km) roadway connects the towns of Georgetown and Grant, Colorado, as it passes through National Forest and Bureau of Land Management properties. Computer renderings of initial design concepts were matched with photos taken on site at many sensitive, scenic zones and merged in the computer to generate a photo-realistic view of the proposed alternatives. In some cases, it was more cost effective to generate a series of wire-frame images that were merged with a site photo. The merged image was then used to develop a series of hand sketches showing alternative design concepts. Another process was developed where color aerial photos were draped over the computer terrain model and then viewed in a series of bird's-eye perspectives.