Within the broad field of landscape assessment, scholarship focused on visual impacts accounted for a very small percentage of peer-reviewed journal articles. There has been even less interest in reviewing the methods being employed to conduct visual impact assessments (VIA) as part of the development permitting process. The purpose of this review has been to show that VIA is not a uniform concept and includes a rich diversity of methods. Six diverse methods are described in some detail, including the assessment instruments, and then comments on the apparent dimensions of this diversity are made. The discussion compares the objectives, criteria, indicators, and standards used by these methods. It also considers whether the VIA is conducted using quantitative or qualitative measurements, professional or public assessors, and a geographic information system (GIS) or key observation point (KOP) framework. It concludes with a discussion of recommendations concerning identifying a gold standard against which to evaluate the VIA methods, the use of multiple methods in a VIA, and the need for research that evaluates the validity and reliability of tools and indicators as they are used in VIA.
