Assessment of Visual Qualities, Impacts, and Behaviours, in the Landscape, by Using Measures of Visibility

Abstract

The application of information technology to landscape analysis dates back to the early work in computer-based mapping. Indeed, much of the early development of what became geographic information systems (GIS) and three-dimensional landscape simulation was undertaken by landscape architects. Mapping of viewsheds quickly became a key element of the landscape-planning process. The process was applied to determination of both view characteristics and potential visual impacts. The algorithms for viewshed analysis were incorporated into GIS products at an early stage in their evolution, but have evolved very little since despite the identification of significant potential enhancements. Extension of the simple binary mapping of GIS has therefore depended on specific developments by individual researchers. These GIS extensions have generated models of visual quality and visual impact using mapped variables. More recently it has become apparent that the essentially two-dimensional approach to view analysis afforded by GIS is inadequate in situations with strong three-dimensional elements. The upsurge in agent-based modeling has demanded a new standard in computer-based visual interpretation of landscape. Both the historic role of GIS-based visual modeling and the potential of 3D-based visual modeling are reviewed.