| Draft Environmental Impact Statement Shorts School Road Am Antenna Structures 27 3.1.1.7 Assessing Visual Impacts Assessing the visual impacts that would be caused by the proposed alternatives involved quantifying visual resource change. Visual impact is difficult to measure and assess. Unlike some impacts, such as degradation of air or water quality, establishing a standard against which to measure and evaluate visual change is not easy. Much of what we value as visually desirable or beautiful depends to some degree on personal values. Also, there is so much information contained in a given visual scene that it is difficult to break it down into the individual components and measure what is being evaluated. That is why a methodology such as that used by the FHWA can be so valuable. By creating a rational, reproducible methodology, the results can be tested by all interested professionals to see if they can be re-created. This reproducibility of results is what allows the final impact rating to avoid accusations of subjectivity and be accepted by the community at large. Visual impact ratings depend on the availability of accurate visual simulations that portray the proposed future conditions. For the proposed KRKO Antenna, photo-realistic visual simulations were developed to illustrate the level of change between existing and proposed visual conditions using the following process and software. AutoCad drawings of the proposed radio Antenna, including design specifications and FAA required colors, were obtained from the manufacturer. These digital drawings were used to model the proposed alternatives in a 3D software program called FORM Z. Using elevation points for the Antenna and GPS coordinates taken in the field, the 3D Antenna models were digitally located on the correct coordinates and the models were input into the viewpoint photographs using Adobe PhotoShop. The computer model also contains a digital topographic model of the surrounding landforms which help accurately place the Antenna within the photograph. The presence of the balloon in the original photograph also helped to ensure the accurate digital placement of the Antenna relative to the main structure. Following preparation of the photo simulations, the vividness, intactness, and unity of the landscape from before and after photographs of each identified viewpoint were evaluated and rated for each alternative. A sample rating sheet, shown below in Table A.3, identifies each of the factors that go into making up the final visual quality ratings. First, individual ratings for vividness, intactness and unity were assigned. Recognizing the role distance plays in human perception, the ratings were developed separately for the foreground (0 to 1/4 mile), middleground (1/4 to 3 miles), and background (3 or more miles) zones of the view. Then, averaged values are obtained for the foreground, middle ground, and background. Once these averages are obtained, there is an opportunity to apply a weighting factor prior to establishing an overall visual quality rating. Also known as a Level of Importance factor, this recognizes that within any given individual view, certain portions of the landscape are frequently likely to have a much greater importance than other areas. For example, objects in the foreground may partially or completely obscure the middle and background of a scene, or a dramatic mountain vista in the background may draw the eye so completely that objects in the foreground are of little importance in evaluating a viewpoint. The ability to apply this weighting factor helps balance out the overall rating. Again, this weighting factor was applied separately to the foreground, middle ground, and background of the individual view. The individual ratings |