Visibility Analysis to Enhance Landscape Protection: A Proposal of Planning Norms and Regulations for Slovakia

The visibility of a landscape is an important aspect of landscape protection planning because different rules or norms can be defined to regulate land-use and human activities depending on the degree of landscape visibility. Viewshed analyses are common GIS-based approaches to evaluate which parts of the landscape can be seen from certain points or by people located or moving in the landscape. In this work, the visibility of the entire landscape of the Slovak Republic is assessed from the network of major national roads. The results of the landscape visibility analysis are then used to propose appropriate planning norms and regulations to protect the identified visibility values and avoid potential visual obstructions from new buildings or infrastructure development. Particularly, the proposed norms indicate allowable changes to the landscape and the maximum height of new or existing buildings and other urban infrastructure. Maps of the spatial distribution of the proposed norms identify possible situations of consistency or conflict with potential urban development trends, to support landscape protection planning processes at the national level. On average, the most visible land-use/land-cover categories are glacial mountains relief, plane depressions, and wide alluvial plains, while the planning indications/prescriptions to protect landscape visibility have been proposed for irrigated land and forests. Thanks to the limited use of geographic datasets, the method ensures high transferability to other different geographic contexts, and allows to derive planning indications for large national contexts.