Visual Impact Assessment
Visual Impact Assessment (VIA) refers to a systematic analysis of potential impacts to scenery and views (positive and negative impacts) resulting from a proposed development. VIA must also include an "investigation of the means available to mitigate the effects of such proposals prior to implementation" (Macaulay). The Macaulay Institute in Scotland is a leader in the study of visual impact analyses. They define visual impact as a “change in the appearance of the landscape as a result of development which can be positive (improvement) or negative (detraction)”.
There is no single precise methodology for VIA. Many companies and software products specialize in various techniques of VIA. VIA is now an essential component to an Environmental Impact Statement (EIS - often referred to as "Environmental Impact Assessment" (EIA)). Environmental Impact Statements examine other environmental impacts of a proposed development such as air and water pollution, effects on flora and fauna, and noise. While most EIS concerns are measured in quantitative terms, "visual impact is assessed largely by qualitative judgements, as it is concerned with the human appreciation of, and interaction with, the landscape" (Macaulay).
Among all the concerns addressed by an Environmental Impact Statement, visual impacts are often the most publicized and contentious. The public may have intense feelings toward a landscape or viewshed, and any development upon this landscape may be considered a degradation. This is especially true of landscapes that are considered "pristine" or "unspoiled" or have other nostalgic, historic, or cultural value.
For a complete and thorough description of Visual Impact Assessment (VIA), refer to the Macaulay Institute page on VIA. This page not only offers a definition for VIA, it also provides historical and contextual background, describes various methods and techniques employed for VIA, and discusses politics and issues concerning VIA.
Companies involved in VIA work on wind projects:
Software often used for VIA analysis for wind projects:
Methods/Guidelines for VIA:
The US based non-profit organization Scenic America has published a useful guide to Visual Assessment Methods, available here.