Visual Impact Assessment in Urban Planning

Nearly half a century has passed since Lynch described visual quality of American cities. Although the issue of visual impact assessment in urban planning is not new, only few experiences exist considering visual aspect when realizing new development zones. Visual aspects are fundamental in urban planning, since each plan choice can generate manipulation or obstruction of urban elements, producing negative effects on the image of the city. Viewshed analysis can help to achieve a more objective and consequently more effective analysis of visual impacts. Traditional viewshed analyses (single, multiple and cumulative) do not show which target is visible from a certain cell. On this purpose, a new viewshed analysis has been developed, the Identifying Viewshed, which shows how many and which objects are visible in several areas. The implemented extension has been tested in three different contexts, Laurenzana and Venosa, in Basilicata Region, and Pisa, in Tuscany.