Viewshed Analysis-Based Method Integrated to Landscape Character Assessment: Application to Landscape Sustainability of Greenhouses Systems

The visual impact of crop shelters in the rural landscape is of paramount importance for the sustainability of landscape planning. It is of utmost importance to protect a beautiful landscape characterized by archaeological sites and natural ecosystems but it is also fundamental to preserve a key economy based on agriculture. To preserve the landscape there is the need to understand its landscape units and to assess the feasibility of the application of landscape character assessment (LCA) at a local scale and adaptation to higher scales in the land-use planning process. In this study, a methodology based on viewshed analysis was integrated into LCA in order to define landscape character areas and types. An application of the method was done on greenhouse systems. Landscape evaluation was carried out by using both ECOVAST guidelines for landscape identification and indicators, which were defined and computed in order to describe the visual impact of greenhouses. The method was applied to a study area located in South Italy, in the Province of Ragusa, in the eastern part of Sicily, where the greenhouse system highly characterizes agricultural activities and made it possible to define landscape guidelines. Finally, a visibility map was drawn up to highlight the areas subject to the greatest visibility. In addition to objectifying the visual impact of greenhouses, the research verified that the proposed LCA-based methodology combined with viewshed analysis can be feasible for supporting the analysis phases of landscape and urban planning under the new territorial governance laws issued for the Region of Sicily in recent years. These analyses were useful to provide information that objectively takes into account the importance of the visual component in the context of landscape planning. Due to the limited surface of the sample area considered in this study, this research work should be considered a pilot or preliminary study. The extension of this methodology to the adjacent municipalities could represent the practical application performed by local authorities to define common regulations suitable to preserve landscape components.